Snailicorn

Snailicorns are large snail-like creatures that appear exclusively in New Super Mario Bros. They appear in only two ice levels, World 5-3 and World 5-B. Each Snailicorn has two small green feet and a single horn on its head, as indicated by the species' name (a portmanteau of "snail" and "unicorn").

Snailicorns walk from side to side on the platform they are found on and turn around to avoid edges if necessary, similarly to red Koopa Troopas. If a Snailicorn sees Mario or Luigi, it will charge in a straight line and attempt to damage them with its horn. While Snailicorns cannot be defeated with jumps or fireballs, jumping on their shells pushes them back, and can be used to push them into gaps within platforms or bottomless pits. Ground Pounds can push them back farther than a normal jump. Snailcorns can be defeated with a shell, a Mega Mushroom, or a Starman.

Trivia

 * The game's internal filename for Snailicorn is a romanization of the Japanese name for Bully, suggesting that it was originally designed as one before being changed to a horned snail. This explains why the two species act in a similar manner. Given that it has one horn and only appears in ice levels, it may have specifically been modeled after Chill Bully.