The common name unicorn snail primarily refers to the species Subulina octona, a small, slender, tropical land snail known in the pet trade as the miniature awlsnail or "Octona Subulina". The nickname comes from its distinctive, pointed, horn-like shell shape. 
 
Key Characteristics
Appearance: The shell is narrow, elongated, smooth, and translucent, appearing pale yellow or brownish due to the snail's body inside. It grows to about 1.5–2 cm (0.6–0.8 inches) in length, though it can reach up to 3 cm.
Behavior: They are nocturnal, social creatures that are very active in their environment.
Origin and Distribution: Native to the tropical Americas and the Caribbean, this species is now globally widespread in tropical and subtropical regions, often found in damp, shaded areas among leaf litter and moss. 
 
In Captivity
Unicorn snails are popular in the terrarium and bioactive setup hobbies due to their hardiness and function as a clean-up crew. 
Diet: They are herbivores and detritivores, primarily consuming decaying plant matter, leaves, fruits, and vegetables. They also rasp on wood and eat tree bark.
Housing: They thrive in humid environments (80%+) with a substrate of coconut fibre, soil, and peat. Good ventilation is important.
Breeding: They are hermaphroditic and can reproduce through self-fertilization, laying eggs with well-developed embryos that hatch in the soil. They are prolific breeders, and colonies can grow quickly.