Wormwood Treefolk — ruling 1

Causing Wormwood Treefolk to gain forestwalk or swampwalk is useful only during the declare attackers step or earlier. Once it becomes blocked, giving it a landwalk ability won't change that.

Wormwood Treefolk : règles, fonctionnement et interactions (MTG)

Wormwood Treefolk is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

: This creature gains forestwalk until end of turn and deals 2 damage to you. (It can't be blocked as long as defending player controls a Forest.) : This creature gains swampwalk until end of turn and deals 2 damage to you. (It can't be blocked as long as defending player controls a Swamp.)

How it works : Wormwood Treefolk

Original English text — Wizards of the Coast / Scryfall

#1October 1, 2009· Wizards of the Coast
Causing Wormwood Treefolk to gain forestwalk or swampwalk is useful only during the declare attackers step or earlier. Once it becomes blocked, giving it a landwalk ability won't change that.
No other card is named in this ruling.