Mantis, or Hopper (ホッパー) in Japan, is a grasshopper-like Badnik from Sonic the Hedgehog 3 found in Marble Garden Zone. They jump when approached, so make sure you don't get below them. They can be easily destroyed with a spin attack.
This Badnik makes a return in Sylvania Castle Zone from Sonic the Hedgehog 4: Episode II, retaining the same attack pattern as in Sonic 3.
||A Grasshopper type robot which was also featured in "MARBLE GARDEN ZONE" in "Sonic 3". Since they can suddenly jump without notice, their moves are unpredictable. Be careful not to bump into them.
— Sonic the Hedgehog 4: Episode II website