From Sonic Retro
Tubinaut is a badnik featured in Studiopolis Zone from Sonic Mania. These badniks are based on Orbinaut from the classic trilogy, but instead of spiked balls, Tubinaut has three colored orb-like devices, one red, one green and one blue. By rapidly spinning the three orbs, Tubinaut generates a multi-colored barrier that can hurt the player. If the player destroys one of the orbs, the power of Tubinaut's barrier is weakened. It will now deflect the player while they are spinning, rather than damage them, but will still damage the player if not spinning. If the player destroys two of the orbs, the barrier is disabled completely, but Tubinaut will still spin the last orb around itself for defense. Attacking Tubinaut's head will destroy it.