A person or thing that is so downright stupid and incompetent that say in the context of starting a band would be placed on either a gong or most likely a triangle; as can be seen in Blackadder goes Forth, during the intro Baldrick chimes a triangle with all the look of a genial miracle worker on his face.
Call her Mindy: So, are you asking Rick to the prom
Call her Samantha: Minds, please. Sure he's hot but the conversation would sink to a dry desert swell within seconds.
Mindy: But the body, oh the body...
Samantha:... and what about it, bitch get in pecking order. You shadow me, got it? Besides, I may even choose this triangle material as my choice before the night is through yet, let's just see.
Mindy: Sure Sam, sure... gee do you think he's got a purdy lookin' packet of meat -
Samantha: - minds, this is the 80s, as if. Can you imagine a guy even offering me that kind of thing, even if he is a baboon who does nothing but jack off in front of the mirror all day... yeah he tells me these things, he finds them quite intriguing. You know what, you take him... when you put two dummys together you're sure to end up with two very quiet mouths, and I'd pay hard coinage - cash Minds - to have you two shut up for just a nanosecond.