But that's supposed to HEAL you!

[MortisLegio]

my own bullets in MW2

I hit a wall and it says I shot myself

 

[the_tramp]

I threw a flashbang in counter strike source at someone, they had 1hp or something because the impact of the flash physically hitting them killed them.

 

[FoolKiller]

phoenix down.

 

[ArtVSscience]

That was like the best part! I have had AED (defibrillator) training, and applied incorrectly they could be fatal. Also notice that they are the classic medical drama style AED. Most AEDs use adhesive patches.

 

[LewsTherin]

Medikit in L4D/2. Wondrous irony.

 

[Khujager]

One time while playing GTA IV I bumped into a ped talking on a cell phone, picked up said cell phone and threw it at his head. He proceeded to stumble backwards into traffic only to get obliterated by a speeding car. I just sat there stunned and then laughed for a good few minutes.

 

[12capital]

Gnome Chompski in Left 4 Dead 2.
http://left4dead.wikia.com/wiki/Gnome_Chompski

The melee is very weak, but it is possible to kill someone with it.

Beat to it. =(
My second answer has to be an exploding fire hydrant in MW2.

 

[Insert Comedy Here]

I beat Splicers to death with Sander Cohen's charred photographed corpse.

 

[Sleekgiant]

A broom in Assassin's Creed 2( I know it can't heal but it was fun grabbing a guard and performing the insta-kill button mash)

 

[Jark212]

In Halo 2 my favorite weapon was a depleted Energy Sword...

Got so many skills...

 

[tthor]

in half-life 2, i once killed myself with a cardboard box

 

[Danglybits]

Water. Turtles. Those are my big two. I loved my friend's reaction when I jumped into a pool in TR; it was the first time she'd seen a videogame where water wasn't an insta-kill.

 

[Kurokami]

A chair in Crysis; I kid you not, I walked into a chair and died.

I threw a person and died.

Fuck you cryengine. (that is what they used right?)

 

[ClaptonKnophlerHendrix]

I threw a soda can at this one muscular korean man in Crysis.
How does a Soda Can send people flying?

Exactly this. I thought that only ever happened to me. Thanks for ruining my individuality.

 

[Sly Skater Man]

Probably the snapping fingers from Bioshock, no matter how long i played the game and used the Incinerate power i couldnt get over the fact that i was looking at people, snapping at them...AND THEN LIGHTING THEM ON FIRE.

 

[S.R.S.]

An egg in re4/5

 

[aarontg]

Speaking of battlefield bad company I played the first game's demo and I killed a terrorist by taking a power tool to his face.

 

[feather240]

Probably the snapping fingers from Bioshock, no matter how long i played the game and used the Incinerate power i couldnt get over the fact that i was looking at people, snapping at them...AND THEN LIGHTING THEM ON FIRE.

Did you snap to a tune?