Snail Blaster
From Sonic Retro
Snail Blaster, or Den-Den (デンデン) in Japan, is a snail-like badnik from Sonic the Hedgehog 3 found in Launch Base Zone. They trudge up and down walls, occasionally opening their shells; this is the chance to attack them, but watch out, they will fire off a pair of flashing projectiles. This badnik made an appearance in the Sonic the Hedgehog OVA.