Bowhead Whale. It's rather rare to see this species breach quite like this. This one was showing off for a female nearby.
If you are having a hard time figuring out what you're looking at, you aren't alone.
This species has a huge lower jaw (left side) and a tiny upper jaw. The eye is just behind the mouth.
Very strange design but common among baleen whales, that is whales that skim out plankton from the oceans

Just outside Baffin Bay near Pond Inlet, Canada
June 2018