It's the kind of "Storage Wars" story that would make Dave Hester proud -- some guy in Maryland bought a unit for $300 at a storage auction recently only to find more Dikembe Mutombo memorabilia than you can shake a giant finger at.

The winning bidder is Adrian Petrus ... who competed for the contents of a forceclosed unit -- and just like on "Storage Wars," Adrian had no idea what was inside.

So you can imagine how pumped he was when he opened the locker and realized the whole thing was packed full of Mutombo items -- signed basketballs, shoes, jerseys, trading cards and photos of Dikembe with celebs like Michael Jackson and Nelson Mandela.

The locker also contained works of art painted and signed by Mutombo's brother.

So who would abandon such an incredible cache of Dikembe stuff?

Turns out, the unit belonged to one of Dikembe's brothers ... who lost the locker recently after missing several rental payments.

We're told the brother had gone back to the Congo to deal with family issues in the wake of his father's death -- and simply forgot to make his locker payments. Sucks.

Petrus tells us .. once he realized what he had, he reached out to Dikembe to try and make a deal to return the items ... but never heard back. So, naturally, the next step ... is eBay.