banana brained 

Original:
"of limited intelligence who can't keep his mind on the task at hand" (adjective refering to a person)
Reference implies a person who has the mental capacity of a monkey or ape and can think only of eating bananas, instead of anything else.
"very dumb" (adjective refering to an idea)
Implies an idea thought up by a monkey or ape.

New: United States Army Specicial Forces term coined sometime after the 2001-2002 war in Afghanistan, meaning specifically "shot to the head" (verb), "a really, really dead _______" {(adjective) usually describing a corpse minus the head}, or "Just got killed in a very bad way" (statement). Statement form generally used in the same context as headshot.

Originated from a very dark humor joke:
Joke teller - "What's the last thing that goes through a terrorit's mind?"
Recipient - "I don't know, what?"
Teller - (At this point the teller holds up a 50 caliber bullet that has been deformed after firing and impact) "I don't know either, but it looks like a banana!"

Original:

Adjective refering to a person -
After the car accident, the first words out of my mouth were "You banana brained moron! Were you even wacting the road!"

Adjectiver refering to an idea-
"Most of the class will be passing, except for young Mr. Smith here. His banana brained political thesis "Toking Presidents = World Peace" has rewarded him the pleasure of being my student next year as well as this."

New:

Verb -
"Damn, Johnson's hit!"
"He gonna make it?"
"No, banana brained."

Adjective -
"I told you he's a crack shot. Look at this poor banana brained fool."

Statement -
"Shot's away. Let's give it two seconds flight time and...ouch. Banana brained."

banana brained by awelltrainedferret May 7, 2007