Please tell me.
According to https://nkpop.com/2014/03/12/this-is-an-attack/ (the first google hit for "공격전이다 english") it's "This is an Attack."
わーい おにいちゃん コンギョするの？
It's translated to "This is an Attack" (공격전이다, Gonggyeokjeonida), but I think "Aggression Momentum" works better.