Fadoodlebop
A fadoodlebop is what you call something you can't name. It's also a name for a thing that doesn't have a name. Or it's a name you give to an island that looks like a trash heap.
'This game is a fadoodlebop. I don't even know what it is.'
'That island is a fadoodlebop. It's just a pile of trash.'
'He named his pet a fadoodlebop. That's the dumbest thing ever.'