Wildgrowth Walker

Oracle Text

Whenever a creature you control explores, put a +1/+1 counter on Wildgrowth Walker and you gain 3 life.

Card Rulings

9/29/2017 If a creature leaves the battlefield before an effect instructs it to explore, it still explores. Effects that trigger when a creature you control explores, such as that of Wildgrowth Walker, trigger if appropriate.
9/29/2017 If Wildgrowth Walker leaves the battlefield while its triggered ability is on the stack, you won’t put a +1/+1 counter on anything but you will gain 3 life.