Basic Trope: Power at a Price — using it costs you your lifespan, sometimes accompanied with Rapid Aging.
- Straight: Bob's Dangerous Forbidden Technique, "Tropebuster", cost him a few months of his lifespan.
- Exaggerated:
- Each use of "Tropebuster" costs him about one year, and he's visibly older after he use it.
- Using Tropebuster will kill him right after it's executed, as it cost him his entire lifespan.
- Downplayed: Cast from Hit Points.
- Justified:
- Every living being has (mostly unreplenishable) Life Energy, Tropebuster is a technique that converts this life force into a deadly attack.
- Losing some of your lifespan is better than losing all of it.
- Bob is a robot, using Tropebuster stresses his system and degenerates it beyond repair.
- Tropebuster (somehow) involves radiation, toxins, and/or heavy substance abuse, which messes up Bob's health really badly.
- Inverted:
- Using Tropebuster increases Bob's lifespan.
- Tropebuster is an attack directed at the enemy's life force, causing Rapid Aging in them.
- Tropebusting is a practice used to extend lifespan at the cost of permanent losses in power.
- Subverted: We see a Distant Finale where Bob is alive and kicking at the venerable age of 108.
- Double Subverted:
- But it's only because Bob had become a lich, he actually died from using Tropebuster a long time ago.
- That is Bob v2.0
- Parodied: After Bob uses Tropebuster, his friends throw a birthday party for him since he has grown older by about one year.
- Zig Zagged: Bob learns the Tropebuster, which is Cast from Hit Points. He (and the audience) thinks that means permanent life force, but it actually uses Ki, which regenerates. Then Bob needs more power for the Tropebuster and has used/is using all his Ki already, so he uses his true life force to fuel it further.
- Averted: No attacks cost lifespan to use.
- Enforced: "The Hero needs an ultimate attack that can reliably win any battle, but one that he can't simply use every time."
- Lampshaded: "I see your aura grow paler every time you use that attack."
- Invoked: Emperor Evulz curses the Tropebuster somehow, or destroys its previous power source, so that it drains Bob's life force.
- Exploited:
- Emperor Evulz baits Bob into using the Tropebuster repeatedly, while he dodges and taunts - or worse, blocks.
- Bob can use the Tropebuster to unleash a devastating attack, in exchange for a few years off his life. Before he uses it even once, he finds a way to make himself The Ageless, as well, effectively allowing him to use a technique that would kill anybody after one use, with the only restraining factor being his own discretion.
- Defied:
- Bob finds a way—fair or foul—to replenish his life force after he uses Tropebuster.
- Bob refuses to use Tropebuster and finds a way to defeat the villain with a different attack or a different method to power the Tropebuster.
- Discussed: "Bob, why would you use an attack that will eventually kill you—literally?" "The years shaved off my life is nothing compared to having to live under Evulz' oppression."
- Conversed: "Bob might love his new firepower now, but let's see how he feels in a few years when he's wasted decades of his life overusing that technique".
- Implied: Bob is shown to be drained a bit every time he uses it. In the epilogue, he is shown to have aged quicker and is the first one to appear in the funeral montages of the heroes dying of old age despite being the youngest of the group.
- Deconstructed: Mastering the Tropebuster skews Bob's world-view. Bob knows that every time he uses it he's closer to death—why should he care about other people's lives?
- Reconstructed:
- Bob can only begin learning Tropebuster after strengthening his soul.
- Whoever invented Tropebuster made sure it lowers lifespan, so only those with a heroic and selfless mindset will use its powers when the need is sufficiently great rather than abusing the technique for personal gain.
- Played For Laughs: Bob uses Tropebuster and turns into a weak old man, visually aging as the power flows out of him. He delivers a humorous one-liner afterward and displays stereotypical old man behaviour. He finds a way to counter the accelerated aging by the end of the episode.
- Played For Drama: This trope is already dramatic in nature.
Returning to Cast from Lifespan will cost you a few seconds of your life
