This card cannot be destroyed by battle. You take no Battle Damage from battles involving this card. Before damage calculation, when this face-up Attack Position card is attacked by an opponent's monster: Inflict damage to your opponent equal to that monster's ATK. During your End Phase: Tribute 1 other monster or destroy this card. When this card is destroyed, except by its own effect: Its owner can Special Summon 1 "Yubel - Terror Incarnate" from their hand, Deck, or Graveyard.
How to Get
Tributes as an effect
Special Summons from your hand / Special Summons from your Deck / Special Summons from your Graveyard
Monster Spirits dueling can do either. (And both have happened.) Jinzo and Don Zaloog Summoned themselves to the field. Dark Magician Girl, Yubel, Kaibaman, etc. Summoned copies. Seems to mostly be an ego thing.
This card would be unstoppable if you could manage to summon it and Northwemko.. And then protect Northwemko I guess