2018-10-05 : Because tokens aren’t cards, they never count for undergrowth abilities.

2018-10-05 : Creature cards with other types, such as artifact creature cards, count for undergrowth abilities.

2018-10-05 : If Vigorspore Wurm gains menace, it can’t be blocked at all.

2018-10-05 : If there are no creature cards in your graveyard, the target creature just gains vigilance until end of turn.

2018-10-05 : The value of X is determined only as the undergrowth ability resolves. If the number of creature cards in your graveyard changes later in the turn, the target creature is unaffected.