That's bananas

Saying something is crazy, ridiculous, or just plain balderdash.

Dee: It's my brother's fault, though. You're not going to believe this. He tried to convince me that you were retarded, what?
Lil' Kev: No, what.
Dee: I know.
Lil' Kev: That's bananas, girl.
Dee: You're not retarded, are you?

That's bananas by Ernie on Crack August 21, 2009

That’s Bananas 

Mind boggling; the craziest shit ever heard; absolutely out of this world info

Casual

When you hear something crazy or exciting but you don’t feel like expressing it

Friend: omg there’s a forest fire the next town over
Me: That’s bananas man

That’s Bananas by Mrnancow November 17, 2022