Thornbite Staff and mana cost

Question

With Thornbite Staff, do you need to pay two mana to untap this card if a creature is put into the grave yard or is the mana cost only for doing one damage to target creature or player?

Answer 1

The mana cost is only for the first ability, dealing the damage.

Thornbite Staff gives the creature 2 complete separate and unrelated abilities. The first is an activated ability; because it has the format {cost}:{effect}. The second is a triggered abilitty, because it starts with the word “whenever”. Each ability is surrounded separately by quotes, with “and” in between.