The idea this: You have swords. You go to the blacksmith and when he forges them to become more powerful, but when you take the Blade of gentle waves to the blacksmith, it turns into the blade of dripping poison.
This trope is basically when when something is reliably and upgrade, leveling up or forging the item, but the upgrade is instead different from the previous versions.
: This can be taken with some paths, it allows you the option to continue with the set path, but you can also upgrade a weapon so that it carries a different element.
The online card game Eelements: when you upgrade a few cards, like Chaos seed which will inflict a random negative status, it will instead turn them into another effect, Chaos power which improves a monster's stats.
If we have this i haven't found it.