Snailicorn

Snailicorns are large snail-like creatures that appear exclusively in New Super Mario Bros. They only appear in two ice levels, World 5-3 and World 5-B. They have two small, green feet and a single horn on their heads, 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, it will charge in a straight line and attempt to damage him with its horn. While they 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 further than a normal jump. Snailcorns can be defeated with a shell, a Mega Mushroom or a Super Star.

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.