Flying, lifelink
Whenever The Haunt of Hightower attacks, defending player discards a card.
Whenever a card is put into an opponent's graveyard from anywhere, put a +1/+1 counter on The Haunt of Hightower.
If The Haunt of Hightower is attacking a planeswalker, the controller of the planeswalker is the defending player.
The Haunt of Hightower’s last ability won’t trigger when a token is put into an opponent’s graveyard.