Take for example the Nekros warframe (class) in Warframe. One of his abilities...well I'll let the quote do the talking:
A blow so powerful, it turns the enemy's very soul into a deadly projectile, damaging all in its path.In action, your character appears to punch, then sends the enemy it hits flying. If it kills the enemy they ragdoll backwards in a manner reminiscent of releasing an inflated, but unsealed, balloon. Sometimes they'll even hit a piece of geometry on the level and end up flying off in random angles. It's a powerful and useful ability, and yet I find myself laughing at half the results it produces.
|He hit the wall and bounced....I hit the floor and laughed|
Hunters were graced with Misdirection, the official ability of RaidRage (tm) and "Btw, you just pulled." Which, aside from its utility, also became both a useful tool for messing with the obnoxious rogue who thinks he is safe in stealth, and helping your group out. This one might be a more trollish use, but admittedly the capability is kind of amusing.
Firefall had Evacuate, which is described as launching you back and leaving a cloud of poison. Sounds nice enough; in reality, it makes a somewhat flatulent deflating sound and flings the character sharply back. At risk of being called crude and uncultured, it became known in my group as the "Death fart" or something equally silly at the time. In the end it became more of a novelty, and was often used to create humorous green-blue clouds in the air more than it was used to defeat enemies.
So what have you found? Any abilities in a game that you can't help but chuckle at when it's used?