Butterfly

 is a mob that spawns in the Fairy Grotto. The Butterfly deals 100 after being hit.

Butterflies respawn in the same spots, at seemingly random intervals.

Trivia

 * The three Butterfly variants appear to be edited versions of a mosquito made by LyeraHeads.
 * The Runic version, which has, doesn't display "Runic" in its name.
 * It cannot be teleported to using the.
 * The Bestiary icon of the Butterfly is an iron golem head like the Automaton or the Endstone Protector Instead of its own head.