It's a standard setup to have heroes race to stop the nigh unstoppable villain before he becomes all-powerful, unseals his true potential, or gets released. However; more often than not, the heroes fail. So, how's the average Farm Boy hero supposed to take on Excruciant, the Omnipotent! without getting turned to a fine red mist within five seconds of opening the door?
Give the baddie a Drama-Preserving Handicap.
To make things more interesting, a handicap is given to that person or organization to give the other a fighting chance. Sometimes this becomes the Kryptonite Factor. Sometimes a person will feign having a handicap and reveal I Am Not Left-Handed. Other times it's a simple moral code holding them back.
This actually works both ways. Heroes who've won the Superpower Lottery, are unstoppable, or just plain badass may be injured (either by being worn down by Mooks on the way or just from falling down the stairs at home), hit with Green Rocks, are being forced to comply some sort of No-Harm Requirement which forces them to not inflict excessive harm if any, are accosted with their Weaksauce Weakness or find out their invulnerability doesn't work with certain things to make the more modestly powered villain (or his Mooks, if he's a non-combatant) an actual threat. Clever antagonists will use tactics and plans that can bring about these handicaps (or advantages to themselves) either by injuring their enemy to the point of barely being able to stand or using Geo Effects. Sometimes the hero himself chooses to be Willfully Weak for any of several reasons...but when he gives his "No More Holding Back" Speech, the villain better be running.
This is often a more ideal solution than using Deus Exit Machina or randomly depowering the character, as it can keep him in the cast with his normal power intact. Related tactics include Amnesia Danger, Forgotten Phlebotinum, and How Do I Shot Web?. This is the opposite of Eyepatch of Power and Disability Superpower, where the handicap is the power. Almost every Enemy Civil War story is about this, as are a lot of Right Hand Versus Left Hand stories where the heroic factions would normally be able to beat the villains if they worked together.
A mundane version of this trope would be the heroes' ammo count in a gunfight. During normal scenes, the heroes will be able to waste ammunition with reckless abandon, shooting at anything and everything but not hitting much of either while the enemy does the same, and barely any mention being given to how many rounds are in the chamber or how many magazines are left. But then sometimes the heroes are counting their rounds, shouting "reloading!" or "last mag! Make it count!", their shots becoming more careful and sparse while the bad guys close in on their position. At this point, the heroes will either start making plans to go out with a bang or hope some Big Damn Heroes show up to pull their asses from the fire.
Game-Breaking Injury and Worf Had the Flu are subtypes. See also Depower and How to Stop the Deus ex Machina. Compare Nerf for changes to a game that weaken something in the interest of gameplay balance. Contrast Kryptonite-Proof Suit.
