Benny is a great sidekick for any other boss. Not so dangerous by himself, but he helps his friends to keep me in place. Seems to be a deep relationship with Aleksander, with the standard tactic: “You root him, I throw with meteors”.
My vote for first place goes to…well, it´s a shared 1st place.
Mad Queen:
Absolutely annoying in SR. Fast…and I have a lot of projectiles proccing, so I have to keep her on distance when fighting other enemies.
Garbagol:
I see him, I leave him where he is. No damage, till all other enemies are dead. I don´t want him in his second phase while fighting multiple enemies. Hits like a truck.