Leyline of the Forests

Green spells and nonmana abilities of green permanents have Assist (Another player can
pay any amount of the spell’s or ability's generic mana cost).

Whenever a player pays for a spell or ability
they don’t control, that player may have target creature get +3/+3 until end of turn. If they
do, exile all other abilities of Leylines.

"Everyone yearns for trees. We get distracted, sure, but everyone wants to see a tree on their way to work."