The Beckoner. This Boss was introduced in the Boss Monster: The Next Level expansion.
The Level Up ability of this Boss is best activated as soon as possible. Torix's ability pairs well with cards that have the ability to destroy Monster Room cards, or that can force an opponent to discard Room cards.
Torix's ability has the potential to combo, essentially infinitely with Witch's Kitchen. As long as the player has one Monster Card in their hand, they can activate the effect of Witch's Kitchen, and then the discarded Monster Room card would go back to the player's hand.
Some people have noted this Boss reminds them of the Legendary Pokemon, Lugia, based off of its appearance.