Aqua Shield

The Bubble Shield (a.k.a. Water Shield or Aqua Barrier) is a power-up item from Sonic the Hedgehog 3, as well as its locked-on form, Sonic 3 & Knuckles. It is obtained either by destroying an item box with a water droplet symbol (pictured), or by collecting a blue gumball in the Bonus Stage.

This shield is the only one of the three obtainable shields that can be used underwater. It absorbs one hit as well as allowing the player's character to breathe underwater. It can also deflect shots from small badniks, such as the Blastoids from Hydrocity Zone.

Although this shield still appears in the Sonic &amp; Knuckles zones (whether or not locked on), there is no water in any of these zones, making other shields preferable after Launch Base Zone.

Sonic can use this shield to bounce and slam downwards, slightly increasing his jump height, but if done on top of a badnik, the player can achieve a vast jumping increase, especially if done in water.

All 4 shields (Normal, Fire, Bubble and Lightning) are hinted to appear in Sonic Generations.