Drill Bit

The Drill Bit is an unused enemy from (and therefore possible Beta Element of) Super Mario RPG: Legend of the Seven Stars. It is extremely notorious for being mentioned several times in the game (and even appearing once), among other various oddities.

Drill Bits seem to be related to Jabbits, and are recolors of them (which virtually confirms the fact that they would've been either stronger or weaker versions of them if they'd stayed in the game). Their only real role in Super Mario RPG is being an unseen prototype lackey for the Smithy Gang (as one of the Manager's Pounders suggests in the game), although one of them actually manages to make an appearance at the end of the initial fight with Smithy (where he is one of three enemies who tells Smithy that it'd be best if he didn't get angry). However, they exist in the game's coding as enemies. Little is known about what role they would play in the game (or even why they weren't used), but it is know that they would say "This is for Yaridovich!" if Mallow attacked them with Psychopath superbly.

Another instance of Drill Bit's surprising amount of publicity is that it was once listed in an old Nintendo Power guide. Drill Bit may be the most well-known unused enemy in any Mario game.

Trivia

 * The Machine Made Yaridovich has an attack called Multiplier! where he splits into four gray Jabbits. These "Jabbits" may actually be Machine Made Drill Bits, especially since Drill Bit seems to have an ambiguous connection to Yaridovich.