'Beavis & Butt-Head' Rapper -- Are You Threatening Me?!?!

The rapper whose song was mercilessly ridiculed by Beavis & Butt-Head last month now lives in fear for her life -- telling TMZ, ever since the episode aired ... she's been receiving horrifying racist threats.

Rapper T-Baby tells us, she's been getting more than a hundred text messages a day since her music video for "It's So Cold in the D" debuted on the MTV show -- but it doesn't stop with texts ... Baby says she also gets verbally accosted on the street.

According to the rapper, the shocking racist text threats include -- "Goodnight n*****, I wish all you f**kers would go back to Africa where you belong not here. Sleep by your window so I can get to you easier."

T-Baby says she doesn't want to involve the police because she's "no snitch" -- but that leaves her with few options ... like changing her phone number, or moving.