ChaosPortal is a challenge-exclusive unit, first appearing in the challenge of 7/1/16. It can polymorph units to random minions (does not charm them), and mass-teleport, moving all units adjacent to the ChaosPortal to completely random locations. It has no upgrades that have appeared yet. As of known player knowledge, the player has never been given this piece in a challenge, rather, it has always been used by the AI.
Strategy: ChaosPortal Edit
Strength: ChaosPortal Edit
The ChaosPortal provides a massive amount of morale, allowing one to survive move decay. Polymorph has a chance to transform units into Portals, making them sitting ducks. Mass-teleport can throw off defensive formations easily, securing a win. ChaosPortal is capable of polymorphing the enemy king if the opportunity arises.
Weakness: ChaosPortal Edit
The ChaosPortal's polymorph can easily work against you, transforming a unit into a Princess that can promote, a Reaver capable of checkmate, or other undesirable piece. Mass-teleport can also put the king into check or even checkmate, so make sure the King is not near the Chaos Portal. The ChaosPortal also boasts poor and awkward mobility, and its absurdly high value leaves it a prime target for trading.