These are the hardest ones: Igneosaur, Maharishi Ghronto, Cyber Joseph. But I'd say igneosaur is the hardest. Igneosaur got patched to be easier on the easier difficulties, though. Not sure if it's still as hard on hard mode. The igneosaur clip is from 1 month ago.
What was the hardest boss?
These are the hardest ones: Igneosaur, Maharishi Ghronto, Cyber Joseph. But I'd say igneosaur is the hardest. Igneosaur got patched to be easier on the easier difficulties, though. Not sure if it's still as hard on hard mode. The igneosaur clip is from 1 month ago.