Ghostface Killah: Martin Shkreli 'Bout to Catch a Big Mama Ass Whoopin'!

You know rap beef is serious when mamas get involved, and Ghostface Killah's just stepped into his feud with Martin Shkreli ... threatening to open a fresh can.

Ghost posted a video rebuttal to the threats Shkreli recently made against him, and this time he brought back up -- his mom and a couple friends ... who made a badass entrance in ski masks.

Just watch ... Shkreli and his goon squad might want to stand down.

Wu-Tang moms ain't nothing to f*** with!