Elder Portal is a trap Room that was introduced in Paper & Pixels expansion.
A card that is mainly used to force a player to discard Spell Cards they may have. After this card has expelled all of its counters, it can be used as 'ammo' for cards like Crushinator. However, the card can receive boosts from other cards like Dizzygas Hallway or Crushinator if another card is destroyed to activate it, so it might sometimes be wise to wait until using a counter is absolutely necessary. The Boss, Chase, can also give this card another counter, thus giving it more damage, and more ammunition towards using its effect.