Prank Injuries

Prank items used in imitating horrifying injuries. May result in Crying Wolf or Deadly Prank.

Examples of Prank Injuries include:

Anime and Manga

When Yotsuba and her father went to a cultural festival at their neighbor Fuuka's high school, one class had a haunted house manned by a girl with the arrow-through-the-head thing. Being five, and not having been exposed to that gag, Yotsuba got really concerned about her well-being...

On Pocahontas, Radcliff's valet Wiggins pulls the old arrow-through-the-head bit.

In ET the Extraterrestrial, Michael's Halloween costume includes a gag item simulating something sharp stuck through his head. ET appears concerned that he's been genuinely injured.
There is a scene in Summer School in which a teacher walks in to find his entire class has apparently been massacred, as they are lying around covered with gaping, seeping wounds. This is shortly revealed to be a prank.
In the third Scary Movie, one of the main character's friends from the previous film fakes these (being expected to die in 7 days as part of the film's status as a parody of The Ring) before being killed off proper.
April Fools Day took this to the extreme.

One Far Side comic had a reversal of the fake-arrow-through-head hat, an indian with a fake rifle stuck through their head.
Sherman's Lagoon: Sherman attempts to pull this gag. The lagoon gang is trying to hide a whale from hunters when Sherman comes up claiming to have been harpooned through the head. Filmore doesn't fall for it and tell him to just "wait over there till this is over."

On the Halloween Episode of Modern Family, Claire pretends to accidentally chop off her hand to scare the girls. They don't fall for it, but as they try to pick up the fake hand, it suddenly jumps up at them and they scream. Turns out it was Phil hiding under the table.
Mike in The Monkees has one of the fake arrows through his head in a few romps.
An episode of Scrubs has Dr Cox put an arrow on a hung over Jordon's head. She doesn't notice even while Cox draws attention to it.

Steve Martin wore a hat that portrayed an arrow through his head as his trademark.

"The arrow-through-the-head was a thing we used to sell at Disneyland," Martin says, "It was just so silly. It was like anti-comedy."

Basically any high end magician/illusionist act. Sawing a person in half, spearing the armoire with swords, etc.

One of the Nice Hats you can now get in Team Fortress 2 simulates a large butcher knife stuck in your head. (This being Team Fortress 2, it may well be an actual butcher knife stuck in your head.)

Ed, Edd 'n' Eddy: in the Big Picture Show movie, Ed and Eddy manage to scare Edd in the gag factory wearing items that portray with a fork and an axe through their heads respectively.