Bloonhead

A person who is either hotheaded, blockheaded or bloonicious.

"I think I'm a bloonhead at doing some activities because I might probably fail."
"I'm a literal bloonhead at this Bloons game wthat's I'm playing!"

Bloonheaded

1. (Informal) hotheaded or blockheaded.

2. bloonicious.

"A bloonheaded teenager."
"I'm so bloonheaded when it comes down to Bloons TD Battles."