SP- Scott Tenorman Must Die, Shakespeare reference?

[Wearia]

I was having a discussion today about this, one of the most infamous of South Park episodes. Someone mentioned that the ending where

DONT LOOK PAST HERE IF YOU DONT WANT TO KNOW
Cartman feeds Scott his parents

is a reference to one work of Shakespeare. I suspected it might be the Rape of Lucrece but further research has been fruitless. I've heard of a poem where a man feeds his daughter's killers to their mother and always suspected it was by old Willy. Am I right and if so what is the work? If not, does anyone know what I'm thinking of?

[pinkfreud]

Titus Andronicus.

[Tracy Lord]

Titus Andronicus. The woman in question is Tamora, Queen of the Goths, and she is served a "meat" pie containing her two sons.

[Larry Mudd]

Yeah, the bait-and-switch where you thought she was trying to feed Marcus Andronicus his own Publius was hilarious.

[Marley23]

I've heard of a poem where a man feeds his daughter's killers to their mother and always suspected it was by old Willy. Am I right and if so what is the work? If not, does anyone know what I'm thinking of?
This does happen in Titus Andronicus (a play, not a poem), but as far as I know it comes from ancient Greek tragedy. Atreus kills Thyestes' sons and serves them to the poor dupe, then shows Thyestes their hands and feet as proof of what he's done. Shakespeare had to know about this.