Fire shield
From Sonic Retro
The fire shield surrounds the player with flames, protecting him from fireballs and lava. In Sonic 3 and Sonic & Knuckles, pressing jump twice with the fire shield will turn Sonic into a fireball which quickly moves across the screen. Tails and Knuckles, however, cannot use this trick.
http://www.captainwilliams.co.uk/sonic/sonic16bit/sonic3/images/firemon.png
Games the Fire Shield has appeared in:
Technical Information
| 14B222 | Uncompressed art location in Sonic 3 |