My husband has a game he plays with the kids at church. They get bored and start begging dad to "make my hand white." This means he has them put their hand in a fist and then Steve proceeds to rub the blood out of the hand, pushing back through to the wrist.
This has the disturbing effect of making their hands look just like a corpse. Right there in church. It's startling and something about the whole game just seems so irreverent. They of course love it.
I just try very hard not to look. It's unsettling to know what my child's hand would look like if there were no blood running through it anymore. It's like he's taken my deepest fears and sat them down next to me in a place where I should be safe from fears.
To the kids it's just a game. They have no associations with death and corpses. they just think it looks cool. Dad just thinks it looks cool.
Mom just thinks she should probably not read so many murder mysteries.