One hallmark of the Platformer is Everything Trying to Kill You, and this killing is usually done by the simple act of touching the player character. Since this collision is injurious to the player and harmless to the attacker, even if the player is permitted more than one injury before death occurs, he might quickly deplete his entire Life Meter before being able to disentangle himself from the enemy. Enemies, particularly bosses, will often have this as a guard against the player Button Mashing and/or rapid fire controllers, which affects the overall length/ease of the fight.