The Maximum Heat Knuckles Attack (マキシマムヒートナックル Makishimamuhītonakkuru?, lit. "Maximum Heat Knuckle") is a move that appears in the Sonic the Hedgehog series. It is a technique used exclusively by Knuckles the Echidna where he attacks several enemies at once at high speed, much like Sonic the Hedgehog's Light Speed Attack.
The Maximum Heating Knuckles Attack first appeared in Sonic Adventure and later its remake Sonic Adventure DX: Director's Cut. To perform the Maximum Heat Knuckles Attack, Knuckles must have obtained the Fighting Gloves. To use it in gameplay, the player must first hold down the Action button (/) to charge the move. Knuckles will then store up power (which is signified by small purple orbs floating around him) until he is surrounded by a pulsing red and purple aura. For as long as the action button is held, Knuckles will maintain the charge, although his speed dramatically decreases as a result. If Knuckles tries to jump, falls off of a ledge while charging his power, gets hit by an enemy, or if the player releases the Action button in an empty area, the charge will be canceled.
Once near one or more enemies, the player must release the Action button. Knuckles will then release the stored power and unleash a chain of attacks, gliding into all nearby enemies at high speed and destroy them. Just like Light Speed Attack, Knuckles leaves a glowing trail behind him with small purple orbs when blasting through the enemies. Using this attack on Chaos 6 will also deal double damage.
In Sonic Shuffle, the Maximum Heating Knuckles Attack is referred to as the Maximum Heat Attack, and is used exclusively by Knuckles the Echidna. In this game, it is Knuckles' Special Attack Ability. After using a special card, the Maximum Heat Attack allows Knuckles can play another 2 cards. However, Knuckles cannot attack if he draws the Eggman card. Also, if Knuckles draws a special card, this will be ignored and he will draw another card.