Obelisk of Urd

Convoke (Your creature can help cast this spell.
Each creature you tap while casting this spell pays
for {1} or one mana of that creature's color.)

As Obelisk of Urd enters the battlefield, choose a creature type.

Creatures you control of the chosen type get +2/+2.

"All living things must abide by the laws of the
shape they inhabit."