Lucki is out of the hospital after getting injured in a violent brawl near ComplexCon ... and he's jokingly asking cops to return his car.

The rapper took to Instagram Monday, showing off bandages on his face and saying that he had hundreds of thousands of dollars and his debit cards inside the vehicle -- jokingly asking if the LAPD were "tryna have some fun."

Lucki also said he had no idea what happened during the chaotic incident ... adding there was "a lot going on."

As TMZ previously reported ... Lucki was surrounded by fans in a parking lot Saturday when an unknown suspect struck him in the side of the face, causing a laceration. Several other people were injured in the chaotic incident, which our law enforcement sources say is investigating as an attempted murder.

Playboi Carti was also nearby when the fight broke out ... though he was not involved in the altercation, according to our sources.