RiskStar

Riskstar is a conceptual badnik that was originally going to appear in the cancelled video game, Sonic X-treme. It has two modes:

 Basic- In the basic mode, Sonic will have to jump on this badnik, while touching its spikes from the side hurts him.

 Advanced- In the advanced mode, Sonic will have to Spin Dash on this badnik, while touching its spikes from the side hurts him.

This badnik was eventually implemented into the game as Spike and Sweep.