Change your preferences here.
When the wielder is affected by burn, freeze, paralysis, poison, or sleep, its Defense is increased by 50%.
Marvel Scale would be a really good ability, but the status effects themselves are a real detriment. Milotic is the only fully evolved Pokemon with it, and while it is very bulky, any status ailment hurts it a lot and the negative effects outweigh the positives, especially when its Defense stat is not very good to begin with. It can be helpful to make up for being caught on the wrong end of a Will-O-Wisp, but don't try to activate it deliberately, as you would with Guts. It just decreases the amount of time it survives.
That said, in Little Cup, Dratini can become a force to be reckoned with through Marvel Scale, as it can use Rest to activate the ability while it is asleep and to make it extremely bulky. At the same time it can set up with Dragon Dance, ensuring it is not useless while sleeping through Sleep Talk, which also happens to remove the negative side-effect of Outrage.
Found in Dream World