Roadhog hooked you while falling to his death. It started to lift you before pulling you in the pit. He died during the lift part of the animation, then the game threw up.

What normally happens: If the Roadhog hook starts with line of sight and he dies like this, his death removes his line of sight. When the LoS is removed after hooking, as per the recent patch notes, the target is returned to where he was standing where he was first hooked.

There are videos posted from time to time in this sub showing a Roadhog hook an enemy while he is being throw in a pit. Usually he's dragging down the person who pushed him in. He starts with LoS. He dies, LoS is broken, then the hooked target is immediately returned to starting location. It's funny to watch a person dragged into a pit behind a Roadhog only to find themselves fly right back up to their starting position when he dies.

In this case, he never had LoS to begin with. This is because the hook has a VERY forgiving up/down hit zone. He can hook things by aiming way above someone's head. Which is what happens here. There was no place to return you to when he died. What looks like is happening is your momentum you had when his hook animation lifted you before it was supposed to pull you in was not canceled on his death. So, you kept flying up.