It has a special ability which makes every monster the opponent places take 1 damage. This is good for a combo with Asgore, as he kills all damaged enemies when placed. And since Beta 6.8, Heats is also good with the Perseverance Deck, as his Effect will give the monsters KR.
However, due to it's fairly low stats it's not all that usefull later on, and it's ability can backfire easily on cards such as Tsunderplane and especially Mettaton NEO, as it basicly gives the opponent a board cleaner without the need of a 2nd card.
And keep in mind that this effect will trigger after the Magic effect of the summoned monster, so if Heats is killed because of the effects of that effect, the monster will take no damage. This can be the case for cards such as Muffet's Pet, Moldessa and Undyne.
As of Beta 8.0.1, this card damages any monster that have been summoned, not just those who have been played from hand. Such cards include Onion San's Tentacles, Gift Bear's Gifts, Bunbun's Bun, Snow Poff's Greater Dog and monsters summoned from Igloo and Lamp.
- Right Tentacle will die instantly, restoring 3 HP to the owner.
- Bun will die instantly, giving +4 ATK to Bunbun, making it start out with 7 ATK right away.
But the biggest change is the fact you can use Big Bob against it, as every new Big Bob will now get damaged, too. This will end up in having a full board of 2/3 monsters, but all damaged.
- 1 Heats: The Big Bobs will all have 2 HP.
- 2 Heats: The Big Bobs will all have 1 HP.
- 3 Heats: There will be a ridiculously long chain reaction of Big Bobs summoned and dying, only to end up with all of them dead.