Clamer

Clamer (Shell Star in Japan) is a clam-shaped Badnik (hence its name) with giant eyes and a spike ball shooter. Clamer appears in Carnival Night Zone of the Sega Mega Drive's Sonic the Hedgehog 3.

Attack pattern
Once the player approaches, Clamer will retract its spike ball cannon, and fire. This Badnik can also be used as a Spring by bouncing off the back of its shell. The only way to defeat this Badnik is by rolling into it, or making a jump that is completely accurate.

Sonic the Comic
A Clamer badnik was seen as part of Doctor Robotnik's badnik army in Sonic the Comic. It was about to be melted down by Robotnik so that its metal could be used in a new improved badnik, after Sonic had foiled one of Robotnik's schemes.

Trivia

 * In Sonic Advance 2 a Badnik named Yado is similar to Yado.