The bloody stain left on a road from plowing into a deer at 60 mph. Usually accompanied with a puddle of antifreeze and may or may not include skid marks
Joe: Did you see that deer smear on hwy 51?
Jim: Yeah, guy must have been going about 70 when he hit that.
The sputtering, semi-solid shits you take the next day after a long night of drinking beer.
Sara (to herself sitting on the toilet): arrrrrrrgggg this sucks, I drank way to many beers!
(Leaves bathroom)
Lenny to Sara: You ok? what the hell was going on in there?
Sara: Oh just the worst case of beersmear EVER
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.