Ghostface Killah from Wu-Tang Clan just made a BIG mistake by mockingMartin Shkreli … according to Shkreli who’s now making a slew of threats against Ghost.

TMZ obtained a video the pharma exec recorded while wearing his hardest sport coat, with 3 masked men standing behind him. Shkreli, who dropped $2 mil for Wu-Tang’s one-of-a-kind album, is pissed Ghostface referred to him as the “Michael Jackson nose kid.” 

You gotta watch his video threat. It’s a little scary, and a lot entertaining. Think ISIS … on ‘SNL.’ The best part — he refers to Ghost by his “government name” … Dennis. Major diss.

Shkreli — who’s still awaiting trial for securities fraud — even threatens to erase GK’s voice from the “Once Upon a Time in Shaolin” album … which you can hear playing in the background. Another reason this is must see.