Flinch

Flinching is what happens to a character when they are hit by an attack. The character will be stunned for a very short period of time, usually just enough to interrupt any attacks or movements. There are certain attacks that do not cause flinching, and ways for a character to avoid flinching. The amount of flinching is reffered to as hitstun. Some attacks cause flinching without any knockback whatsoever.

Attacks that do not cause flinching

 * Fox's Blaster
 * Mario's F.L.U.D.D. and Cape
 * Squirtle's charged Water Gun
 * Luigi's Super Jump Punch (only in Melee)
 * Snake's Grenade (the actual Grenade; not the explosion)
 * Olimar's Pikmin when latched on.
 * The Bulborbs of Olimar's End of Day
 * The flame of Charizard's forward aerial
 * The rain that occurs in the "Kitty Cover" game in the stage WarioWare, Inc.
 * Glancing Blows

Attacks that cause flinching with no knockback

 * Falco's Blaster
 * Most rapid Attack combos
 * Stafy
 * Diffusion Beam (the spiral rays)
 * Luigi's Super Jump Punch (in Brawl, non-sweetspotted)
 * Super Scope, Charge Shot, Shadow Ball, and Aura Sphere (uncharged)
 * Mach Tornado
 * Bullet Seed
 * Ness's PK Fire
 * Fire Breath and Flamethrower

Ways to prevent/reduce flinching

 * Metal Box
 * Super Mushroom
 * Certain Stickers (only in the Subspace Emissary)
 * Any moves that offer knockback resistance.