Ultimate collector

Some twat, usually a child, who amasses large collections of worthless items, like toys, baseball cards, or comic books. They typically assume, incorrectly, that their ownership of those thing means they are more knowledgeable than others about the product.

Bob: "Why does that cunt over there have so many fucking Legos?"

Tim: "He's some shithead ultimate collector who thinks he's a Lego god."