Bubbles

Bubbles (ハリセンボ Harisenbo) is one of Dr. Robotnik's Badniks that made its debut in Sonic the Hedgehog 3. Looking deceivingly innocent with his smooth, blue exterior, Bubbles has hidden spikes that pop out of its body.

Sonic the Hedgehog 3
Bubbles inhabits Marble Garden Zone located on Angel Island. Like many of the Badniks in Marble Garden Zone is very deceiving in its appearance. Seemingly harmless at first, Bubbles will release its spikes quickly and without warning, causing expected damage to any nearby Hedgehog, Fox or Echidna.

Sonic the Hedgehog 4
Bubbles makes its return in Sonic 4. This time there is a number of variations in color and attacks in different Bubbles badniks. The traditional Blue Bubbles with spikes is present. However due to Robotnik's budget cuts, some Bubbles will not have any spikes. Red colored Bubbles are making their debut in this game as well. Red Bubbles are said to be more difficult than blue.