If this comic is to be believed, getting slapped by a Pizza gives you bruises all over your body and a scratch.
Girl Genius alternates between playing this straight for laughs (Othar Tryggvassen, Gentleman Adventurer! being thrown out of a zeppelin, and it's stated that he's survived worse) and subverting it for character consistency (this strip is Moloch von Zinzer playing the epic klutz, but the last panel shows Agatha looking shocked and worried, possibly because the last time they had seen one another they were pretending to be lovers).
More likely, because Othar is the only person in the series explicitly Made of Iron (though the Jagermonsters come close - Dimo's severed arm is played for laughs, too). Moloch was lucky.
...and then there's the occasional instance (or hour) of unbearable pain for the Light Warriors when Sarda (a near-omnipotent immortal Jerkass) decides to screw with them for his own amusement.
Gordon Frohman of Concerned (a comic based on, and made with, Half-Life 2) has survived just about everything that could possibly kill a player in that game, always played for cartoonish laughs. He was a zombie for a while, but got better then, too. Cruelly subverted at the very end of the comic, when he falls from the roof of the Citadel tower and is Killed Off for Real.
This is because He had Buddha Mode activated the whole time and accidentally turned it off right at the end.
Happens now and then in Sluggy Freelance, usually as a result of someone making Bun-Bun mad.
Any harm involving Richard in Looking for Group. If he's the victim, expect a funny comment from him.
Nodwick - Many strips begin or end with the titular henchman completely wrapped in healing duct tape (in lieu of actual bandages). It seems to be quite effective; his employers frequently use him as a projectile or monster chow.
Averted in MegaTokyo. The writer specifically says he didn't want characters to be able to just shrug off injuries, regardless of how ridiculous they were, so early on Largo breaks his arm in a classic "funny injury" moment - and actually does spend six weeks in a cast.
A general rule of thumb for Las Lindas is that Miles + pain = instant comedy.