Which character uses the 'Sonic Boom' projectile?

Guile uses the Sonic Boom projectile. In Street Fighter II, the American Air Force fighter launches the attack by drawing his arms together and thrusting them outward, sending a spinning wave of energy across the screen.

The Sonic Boom is one of Guile's two signature special moves, alongside the Flash Kick. Its charge-based input rewards defensive play: Guile can hold a direction while blocking or positioning himself, then quickly release the stored charge to fire. This gives him strong control over space and makes him especially effective at forcing opponents to approach.

The move is sometimes confused with Ryu and Ken's Hadoken because both are horizontal energy projectiles. Their execution and visual design differ, however, and the Sonic Boom is specifically associated with Guile. Guile debuted as one of the eight selectable World Warriors in the 1991 arcade release of Street Fighter II, where his story centers on avenging his friend Charlie against M. Bison.