The FBI is investigating death threats against former "Chaci" Scott Baio for posting an unflattering picture of Michelle Obama online.

The Happy Days and Joanie Loves Chachi star ignited a sh*tstorm of controversy when  he posted an unflattering picture of  Michelle Obama on Twitter.

Baio captioned the pic with:  "Wow. He wakes up to THIS every morning."

The off-handed remark drew the incensed wrath of Baio’s followers.

Baio finally Tweeted, "People need to relax and laugh a bit. Life is too short no matter what party you are with. A joke is just that, a joke."

The star insists the reaction to his gag escalated into venomous comments, and he says many messages he received now became threatening.

"Please Note: The FBI has been contacted & we have a file number for the threats, along with Twitter support. Thx (thanks)." Baio, an often outspoken Republican, responded to the online H8ers.