If you do not have the tribute, it will spawn in what it’s asking for and you have to kill it. It’ll give you credit. You only have 4 times to not have the tribute, then the Altar is destroyed.

Trophies

Alpha Deathworm Trophy

Alpha Rex Trophy

Alpha Wyvern Trophy

Tributes

Allosaurus Brain

Alpha Carnotaurus Arm

Alpha Raptor Claw

Alpha Tyrannosaur Tooth

Argentavis Talon

Cerato Venom Spine (unconfirmed)

Giganotosaurus Heart

Megalania Toxin

Sarcosuchus Skin

Sauropod Vertebra

Spinosaurus Sail

Therizino Claws

Thylacoleo Hook-Claw

Titanoboa Venom

Tyrannosaurus Arm

Wyvern Talon (Fire, Lightning, Poison)

Yutyrannus Lungs