Mutant Krill are enemy guards encountered in the level Arctic in the game Sly Cooper 5: Thieves Be Forever. They are one of Vostok's rooftop guards
These oversized krill are orange in color like normal krill and have lots of arms. They wear black boots and appear to stand upright and only have 2 feet, they wear Vostok's "Gill Air 2.0" on their backs. Their devices also function as jet packs that can shoot surprisingly damaging water, they communicate with rather strange bug-like noises and the sounds of their hands moving.
To attack, they do a similar attack that Arpeggio's rooftop Toucans did when close, when far, they charge ahead with their jet pack speed. When very close, they wriggle their many arms like the Hopping Vampires in China that does minor damage.
- Like Vostok's other guards, when thrown in the water, they jump back out no matter how far.
- In concept art, these guards were going to be Snowy Owls.