This guy is a joke.

Just when you thought Michael Lohan could not get any more reprehensible, court documents reveal that the deadbeat dad, well, really is a deadbeat dad.

He's $15,000 behind in child support. Guess those business deals with Jon Gosselin never came to fruition, or he just had all the cash deposited offshore.

Either way, he couldn't come up with $15K?!

Michael has racked up $15,100 in unpaid child support to ex-wife Dina for their three minor children: Ali Lohan, Michael Lohan, Jr., and Dakota Lohan.

Yes, there is a Dakota Lohan, age 13. Scary.

Michael Lohan continues to redefine pathetic.

How about this for irony. If Michael profited off those phone tapes of Lindsay at her lowest points that he released to Radar Online, he could actually support the three children ... with money he made from exploiting his oldest child.

Pack lightly where you're headed, Michael.