The actor sold off the prop for $843,750 Tuesday through Propstore Auction -- a popular site for fanboys and fangirls to buy their favorite movie and TV super collectibles.

Propstore says the head matches several scenes from the film, and it was the only head still in a private collection before it was sold -- as of yet, it's still unclear exactly who bought it.

The fiberglass head -- made up of three components -- still lights up ... so the lucky mystery buyer's got a pretty dang cool new addition to what we imagine is already a stacked "Star Wars" collection.

As for why he's selling ... Daniels told The Hollywood Reporter last week all his 'Star Wars' stuff's just gathering dust in boxes and cupboards -- and he'd rather it go on display or to someone who might really enjoy it.

The head wasn't the only thing Daniels put up for auction either ... he also sold a custom Pittsburgh Penguins hockey jersey given to him by the team after he participated in a charity event as well as a gingerbread cookie given to him on his last day of shooting 'The Last Jedi,' among other wild items.

While the head may be sold, a ton of other "Anthony Daniels" collection items are still up for sale ... so hop over to Propstore quickly before they're all sold off.