Deep-sea gigantismIn zoology, deep-sea gigantism, or abyssal gigantism, is the tendency for species of deep-sea dwelling animals to be larger than their shallower-water relatives across a large taxonomic range.3 min / Deep Animal cognitionAnimal cognition encompasses the mental capacities of non-human animals, including insect cognition.3 min / Deep Nature: BioluminescenceBioluminescence is the production of light by an organism as the result of a chemiluminescence reaction.3 min / Deep Nature: CordycepsCordyceps is a genus of ascomycete fungi (sac fungi) that includes over 260 species worldwide, many of which are parasitic.3 min / Deep Nature: ExtremophileAn extremophile (from Latin extremus 'extreme' and Ancient Greek φιλία (philía) 'love') is an organism that is able to live or even thrive in extreme environments, such as extreme temperature (hot or cold), pressure, radiation, salinity, or pH level.3 min / Deep Hydrothermal ventHydrothermal vents are fissures on the seabed from which geothermally heated water discharges.3 min / Deep Nature: TardigradeTardigrades ( ), also known as water bears or moss piglets, are a phylum of eight-legged segmented micro-animals.3 min / Deep Whale fallA whale fall occurs when the carcass of a whale has fallen onto the ocean floor, typically at a depth greater than 1,000 m (3,300 ft), putting them in the bathyal or abyssal zones.3 min / Deep Amorphophallus titanumAmorphophallus titanum, the titan arum, is a flowering plant in the family Araceae.3 min / Deep Armillaria ostoyaeArmillaria ostoyae (synonym A. solidipes) is a pathogenic species of fungus in the family Physalacriaceae.3 min / Deep Nature: AxolotlThe axolotl ( ; from Classical Nahuatl: āxōlōtl ; Ambystoma mexicanum) is a species of mole salamander.3 min / Deep Nature: BarreleyeBarreleyes, also known as spookfish (a name also applied to several species of chimaera), are small deep-sea argentiniform fish comprising the family Opisthoproctidae found in tropical-to-temperate waters of the Atlantic, Pacific, and Indian Oceans.3 min / Deep Blood FallsBlood Falls is an outflow of an iron(III) oxide–tainted plume of saltwater, flowing from the tongue of Taylor Glacier onto the ice-covered surface of West Lake Bonney in the Taylor Valley of the McMurdo Dry Valleys in Victoria Land, East Antarctica.3 min / Deep Nature: BrinicleA brinicle (brine icicle, also known as an ice stalactite) is a downward-growing hollow tube of ice enclosing a plume of descending brine that is formed beneath developing sea ice.3 min / Deep Catatumbo lightningThe Catatumbo lightning (Spanish: Relámpago del Catatumbo), also known as The Everlasting Storm, is an atmospheric phenomenon that occurs over and around Lake Maracaibo in Venezuela, typically over a bog area formed where the Catatumbo River flows into the lake.3 min / Deep Cave of the CrystalsCave of the Crystals (Spanish: Cueva de los cristales), also known as Naica Cave (Spanish: Cueva de Naica) or the Giant Crystal Cave, is a cave connected to the Naica Mine at a depth of 300 metres (980 ft), in Naica, Chihuahua, Mexico.3 min / Deep Crown shynessCrown shyness (also canopy disengagement, canopy shyness, or inter-crown spacing) is a phenomenon observed in some tree species, in which the crowns of fully stocked trees do not touch each other, forming a canopy with channel-like gaps.3 min / Deep Electric eelThe electric eels are a genus, Electrophorus, of neotropical freshwater fish from South America in the family Gymnotidae, of which they are the only members of the subfamily Electrophorinae.3 min / Deep Nature: ErgotismErgotism (pronounced UR-gət-iz-əm) is the effect of long-term ergot poisoning, traditionally due to the ingestion of the alkaloids produced by the Claviceps purpurea fungus—from the Latin clava "club" or clavus "nail" and -ceps for "head", i.e. the purple club-headed fungus—that infects rye and other cereals, and more recently by the action of a number of ergoline-based drugs.3 min / Deep Fairy circle (arid grass formation)Fairy circles are circular patches of barren land, varying between 2 and 12 metres (7 and 39 ft) in diameter, often encircled by a stimulated growth of grass.3 min / Deep Fatal insomniaFatal insomnia is a neurodegenerative prion disease that results in trouble sleeping as its hallmark symptom.3 min / Deep Ice circleIce discs, ice circles, ice pans, ice pancakes or ice crepes are a very rare natural phenomenon that occurs in slow moving water in cold climates.3 min / Deep Kuru (disease)Kuru was a rare, incurable, and fatal neurodegenerative disorder that was formerly common among the Fore people of Papua New Guinea.3 min / Deep Lake KivuLake Kivu () is one of the African Great Lakes.3 min / Deep Lake NatronLake Natron is a highly alkaline salt lake located in north Ngorongoro District of Arusha Region in Tanzania with its far northern end crossing into Kajiado County and Narok County in Kenya.3 min / Deep Mammatus cloudMammatus (also called mamma or mammatocumulus, meaning "mammary cloud") is a cellular pattern of pouches hanging underneath the base of a cloud, typically a cumulonimbus raincloud, although they may be attached to other classes of parent clouds.3 min / Deep Nature: ManchineelThe manchineel tree (Hippomane mancinella), also known as the tree of death, is a species of flowering plant in the spurge family (Euphorbiaceae).3 min / Deep Mantis shrimpMantis shrimp are carnivorous marine crustaceans of the order Stomatopoda (from Ancient Greek στόμα (stóma) 'mouth' and πούς (poús) 'foot').3 min / Deep Mimic octopusThe mimic octopus (Thaumoctopus mimicus), also known as the shapeshifting octopus is a species of octopus from the Indo-Pacific region.3 min / Deep Morning Glory cloudThe Morning Glory cloud is a rare meteorological phenomenon consisting of a low-level atmospheric solitary wave and associated cloud, occasionally observed in different locations around the world.3 min / Deep Movile CaveMovile Cave (Romanian: Peștera Movile) is a cave near Mangalia, Constanța County, Romania discovered in 1986 by Cristian Lascu during construction work a few kilometers from the Black Sea coast.3 min / Deep Ophiocordyceps unilateralisOphiocordyceps unilateralis, commonly known as zombie-ant fungus, is an insect-pathogenic fungus, discovered by the British naturalist Alfred Russel Wallace in 1859.3 min / Deep Portuguese man o' warThe Portuguese man o' war (Physalia physalis), also known as the man-of-war, bluebottle, or sometimes called Caravela Portuguesa (a name of Portuguese origin), is a marine hydrozoan found in the Atlantic, Indian, and Pacific oceans.3 min / Deep Rafflesia arnoldiiRafflesia arnoldii is a species of flowering plant in the parasitic genus Rafflesia within the family Rafflesiaceae.3 min / Deep Richat StructureThe Richat Structure, or Guelb er Richât (Arabic: قلب الريشات, romanized: Qalb ar-Rīšāt, Hassaniyya: ), often called the Eye of Africa is a prominent circular geological feature at the northwestern edge of the Taoudeni Basin, on the Adrar Plateau of the Sahara.3 min / Deep Sailing stonesSailing stones (also called sliding rocks, walking rocks, rolling stones, and moving rocks) are part of the geological phenomenon in which rocks move and inscribe long tracks along a smooth valley floor without animal intervention.3 min / Deep Nature: SiphonophoreSiphonophores (from Ancient Greek σίφων (siphōn), meaning "tube" and -φόρος (-phóros), meaning "bearing") are cnidarian animals of the hydrozoan order Siphonophorae.3 min / Deep Sprite (lightning)Sprites or red sprites are large-scale electric discharges that occur in the mesosphere, high above thunderstorm clouds, or cumulonimbus, giving rise to a varied range of visual shapes flickering in the night sky.3 min / Deep Turritopsis dohrniiA tiny jellyfish can revert to an earlier life stage under stress.7 min / Easy CordycepsA group of fungi is famous for parasitic life cycles and dramatic hosts.8 min / Easy Ophiocordyceps unilateralisThe fungus behind zombie-ant behavior manipulates insects with unnerving precision.8 min / Easy PrionMisfolded proteins can spread disease without DNA or RNA.10 min / Medium Kuru (disease)A prion disease revealed links between culture, medicine, and protein misfolding.8 min / Medium Fatal familial insomniaA rare inherited prion disease attacks sleep itself.8 min / Medium ErgotismFungal toxins in grain caused convulsions, hallucinations, and historical outbreaks.8 min / Easy ManchineelA Caribbean tree is infamous for toxic sap, fruit, and smoke.7 min / Easy Rafflesia arnoldiiA parasitic plant produces enormous flowers with a carrion smell.7 min / Easy WelwitschiaA desert plant can live for centuries with only two continuously growing leaves.7 min / Easy Lake NatronA caustic lake in Tanzania preserves animals in stark mineral crusts.7 min / Easy BrinicleA sinking tube of cold brine freezes seawater below Antarctic ice.6 min / Easy Sailing stonesRocks in Death Valley move across a dry lakebed under rare conditions.7 min / Easy Blood FallsAntarctica's red outflow reveals iron-rich water and hidden microbial worlds.7 min / Easy Catatumbo lightningA Venezuelan lightning hotspot produces extraordinary storm frequency.7 min / Easy Morning Glory cloudA rare rolling cloud formation can stretch for hundreds of kilometers.7 min / Easy BioluminescenceLiving organisms produce light for hunting, signaling, defense, and wonder.8 min / Easy ExtremophileLife thrives in heat, acid, pressure, radiation, and other brutal conditions.8 min / Medium TardigradeMicroscopic animals survive extremes that would kill most life.7 min / Easy AxolotlA salamander famous for regeneration remains larval throughout its life.7 min / Easy Mimic octopusAn octopus changes shape and behavior to imitate other animals.7 min / Easy Mantis shrimpA marine crustacean has powerful strikes and unusual vision.7 min / Easy Portuguese man o' warA floating colonial organism is often mistaken for a jellyfish.7 min / Easy Electric eelA fish uses high-voltage electric discharges for hunting and defense.7 min / Easy Crown shynessThe upper branches of some trees leave narrow channels between neighboring crowns.7 min / Easy Fairy circle (arid grass formation)Bare circular patches form repeating patterns across dry grasslands in Namibia and Australia.8 min / Medium Movile CaveA sealed Romanian cave supports an ecosystem powered largely by chemosynthesis rather than sunlight.8 min / Medium Lake VostokA vast Antarctic lake has remained buried beneath kilometers of ice for millions of years.9 min / Medium Lake KivuA deep African lake stores enormous quantities of dissolved carbon dioxide and methane.8 min / Medium Richat StructureConcentric rings in the Sahara form a geological landmark visible from orbit.7 min / Easy Cave of the CrystalsA chamber beneath Naica, Mexico, contains some of the largest natural gypsum crystals ever found.7 min / Easy Mammatus cloudPouch-like cloud formations hang beneath storm anvils and create an unusually textured sky.6 min / Easy Red spriteLarge electrical flashes can bloom high above thunderstorms for only milliseconds.7 min / Easy St. Elmo's fireA glowing plasma can gather around pointed objects during strong atmospheric electric fields.7 min / Easy Ice circleSlow currents can rotate sheets of river ice into near-perfect discs.6 min / Easy Tongue-eating louseA marine parasite replaces a fish's tongue and then occupies its place inside the mouth.7 min / Easy BarreleyeA deep-sea fish looks through a transparent shield with tubular eyes that can rotate toward prey.7 min / Easy SiphonophoraeColonies of specialized animals cooperate so closely that they appear to function as one organism.8 min / Medium