Mimkey is a gecko-like Slug that is first seen in the episode Undertow; its ability is to copy the other Slugs's powers. When transformed, it appears as a red-tinted version of the opposing slug's transformation. The only known Mimic Slug belongs to pirate captain, Malvolio Drake. It was given to him by his brother, Brutale, for his birthday. It is also the only slug with defined arms and legs with a tail.
- MirrorMimic - Mimics the "Abilities" and appearance of the other Slug exactly.
- In the episode "Deep Water, Dark Water", a Shark ate Malvolio Drake's Mimkey and it was not seen in "The Gentleman and the Thief".
- It is also shown that if there are multiple slugs it will mimic the slug that is shown the most, even if that Slug is not being shot. (i.e. Vinedrill).
- They appear in Battle For Slugterra but are larger than in the show and are referred to as "Mimics", not even transforming. This may be an entirely separate species of animal that just shares the same features of a Mimkey.