Bloodrush

Bloodrush is an ability word introduced in Gatecrash, wherein it is the Gruul Clans guild mechanic. It is a modal mechanic, with a moderately-sized creature on one "side" and a secondary mode of being able to be discarded in order to give an attacking creature a temporary power/toughness boost equal to the power and toughness of the discarded creature card, along with any combat-related abilities the creature had. This allows for drafters to sustain a quota of combat tricks without stranding themselves when without creatures.

The mechanic scored lukewarm reception and interesting designs were narrow, resulting in a 6 on the Storm Scale.

Rulings

 * The bonus for each bloodrush ability is tied to the power, toughness, and other abilities of the creature card with bloodrush.
 * Since this is an ability of the card being discarded, it's not an actual spell being cast.