Slicer

Slicer (Kamakiller カマキラー) is a mantis-like robot built by Doctor Eggman. It appeared as an enemy in the Metropolis Zone in Sonic the Hedgehog 2 and in Mad Gear Zone in Sonic the Hedgehog 4: Episode 1. It uses it's claws as boomerangs, which are surprisingly hard to avoid. In Sonic the Hedgehog 4, after throwing their claws, they self-destruct if left alone for a while.Slicers are very infamous for their somewhat unavoidable placements.