Insta-Shield

The Insta-shield, known as the W Spin Attack or W Kaiten Attack (W回転アタック) in Japan, is a move that can be performed by Sonic the Hedgehog and Tails (Sonic Advance 3 only). It first appeared in Sonic the Hedgehog 3. The attack is performed by tapping one of the jump buttons while Sonic is in mid-air after already performing a Spin Jump. It has since appeared in later 2D games, in particular the Sonic Advance series.

The Insta-shield will generate a quick shield around Sonic or Tails that can briefly protect them from falling into an enemy, or avoiding projectiles. It also expands the range of their Spin Attack, damaging enemies that their spin jump does not quite reach.

The Insta-shield cannot be used while Sonic is equipped with a shield in Sonic 3. Instead, he will perform an action depending on the type of shield possessed:
 * A Fire Shield will allow Sonic to Jump Dash.
 * An Electricity Shield (also called a Lightning Shield) will allow Sonic to double jump.
 * A Water Shield (also called a Bubble Shield) will allow Sonic to slam downwards and bounce. Sonic can use this to increase his jump height slightly.
 * While in his hyper form, Sonic will perform the Hyper Flash.

The Insta-shield cannot be used in many recent games, particularly 3D games, having been replaced by the Jump Dash or Homing Attack.

The Insta-shield returns in Sonic Advance and is performerd in the same manner as it is in the Sonic 3 & Knuckles. It reappers again in Sonic Advance 2 but if near a normal Badnik Sonic will do a Homing Attack instead. In Sonic Advance 3 both Sonic and Tails can use this move when teamed up with Knuckles by pressing the attack button in midair. In Sonic Generations as a skill for Classic Sonic under the name Twin Spin Attack. The skill is unlocked by collecting all the Red Star Rings in Act 1 of Sky Sanctuary and costs thirty points to equip.

Sonic the Comic
Sonic used the Insta-shield (unnamed in this continuity) twice in issues of Sonic the Comic: first to protect himself from a Pointdexter in the Marble Garden Zone shortly after visiting the Floating Island for the first time, and again while fighting Knuckles. Sonic explained that he created the forcefield by vibrating the air molecules around him at super speed.