ass is grass 

Yes, it does imply the addressee's doom, but for a slightly different etymology, see the quote below:

Sergeant to buck private: "Your ass is grass and I'm the mower."

ass is grass by Graycard May 12, 2008

ass is grass 

In the Bible, the phrase ''all flesh is grass'' occurs. Meaning that life is fleeting.

Somebody rang the changes on it, and so, ''your ass is grass'' comes about. A gaudy threat, or a prophesy of coming misfortune.

"If you snitch on me, your ass is grass"

"The platoon sergeant says Smith's ass is grass when the CO finds out"

ass is grass by Mors Profundis December 3, 2016

Ass is Grass and i'm gonna mow it 

a quote from Bob's burgers that Tina says. When someone's about to get beaten

Wow. She messed up so now her ass is grass and i'm gonna mow it

Ass is Grass and i'm gonna mow it by bobsburger January 1, 2017

ass is grass and i'm gonna mow it 

simply it means i'm gonna beat the fuck out you

Person 1: You dirty bombastic bitch

Person 2: Ohhhh no tf you didn't ..... Your ass is grass and i'm gonna mow it

ass is grass and i'm gonna mow it by Ass is grass December 3, 2015

Your ass is grass 

Your precious buttocks has now become the center of a very farcical taunt. This phrase implies that "you are going down" in the near future. This phrase being said to you means that your inevitable fate is nearing. It is only half of the full sentence "your ass is grass and i'm gonna mow it." Basically someone is threatening you and you better get the hell outta dodge.

"You fucked my wife enough times Todd, your ass is grass!"

Your ass is grass by grassy ass lover 1234 December 28, 2016

your ass is grass and I'm the mower 

Approximates to: You just fucked up big time, and now you're answering to me! Originated in the military.

Commanding Officer: You tried drifting a Humvee till it went Tango Uniform and then blamed it on your bunkmate?! Your ass is grass, boy, and I'm the mower!

your ass is grass and I'm the mower by anonymous January 29, 2005

Your ass is grass 

1.You're dead fool.
2.You better watch it cuz you don't know who you are messing with.

Joe: You are a slut.
Stacey: Say it again and your ass is grass.

Your ass is grass by rebel27 December 18, 2008