Wall of Roots

Oracle Text

Defender

Put a -0/-1 counter on Wall of Roots: Add G to your mana pool. Activate this ability only once each turn.

Card Rulings

11/17/2017 If you must sacrifice a creature to pay a casting or activation cost that also includes mana, such as that of Bubbling Cauldron’s abilities, you may put a -0/-1 counter on Wall of Roots to make its toughness 0 and then sacrifice it to pay that cost.