why does blood come out a movie characters mouth when they get shot or stabbed

[Sirballin]

i watched scream 2 when the ghostface guy killed some black dude in the stall next to him and he stabbed him on the side of the head weird huh? also I watched avengers infinity war when iron man got stabbed by thanos (but didn't die) and then he coughed blood. Any science explanation here?

[Enriquez]

Quentin Tarantino upgrades the effect.

[Jinn-Gon Qui]

I think you just answered your own question there: "...when iron man got stabbed by thanos... he coughed blood."

I think that's the reason.

[ゆのーさん]

it looks cool and stuff

[Jaquaviontavious Bonqueque XVI]

Cause they think it will look cool.

[Shark Bait]

When a lot of your blood holding parts get popped the blood runs away in fear.