“Animal House” star Tim Matheson says he’s getting threatened with way more than a food fight after tweeting something “ignorant” about the former First Lady.

Law enforcement sources tell TMZ … Matheson told cops someone’s been harassing him online since he took a jab at Melania Trump last month, by saying it was wonderful to have a First Lady who can speak English.

Ironically, it’s the kinda thing you’d expect to hear from Melania’s husband.

Tim later apologized, but we’re told the threats keep escalating — from the person saying they’re going to kick Tim’s ass to … “pay me big bucks or I will kill you.”

Our sources say the actor contacted the LAPD after the death threat, filed an extortion report because of the money demands … and now cops are investigating.

As for Tim’s Twitter snafu — he replied to Melania’s farewell message on Twitter to say sorry. He wrote, “Thank you for your work as the First Lady.I apologize to you for a stupid, ignorant,& foul remark that I made.”