Stirring Wildwood

This land enters tapped.
{T}: Add {G} or {W}.
{1}{G}{W}: Until end of turn, this land becomes a 3/4 green and white Elemental creature with reach. It's still a land.

Ultimate Masters

Stirring Wildwood enters the battlefield tapped.
{T}: Add {G} or {W}.
{1}{G}{W}: Until end of turn, Stirring Wildwood becomes a 3/4 green and white Elemental creature with reach. It's still a land.

Ultimate Box Topper

Commander 2017

Stirring Wildwood enters the battlefield tapped.
{T}: Add {G} or {W} to your mana pool.
{1}{G}{W}: Until end of turn, Stirring Wildwood becomes a 3/4 green and white Elemental creature with reach. It's still a land.

Duel Decks: Zendikar vs. Eldrazi

Stirring Wildwood enters the battlefield tapped.
{T}: Add {G} or {W} to your mana pool.
{1}{G}{W}: Until end of turn, Stirring Wildwood becomes a 3/4 green and white Elemental creature with reach. It's still a land. (It can block creatures with flying.)

Worldwake

A land that becomes a creature may be affected by "summoning sickness." You can't attack with it or use any of its {T} abilities (including its mana abilities) unless it began your most recent turn on the battlefield under your control. Note that summoning sickness cares about when that permanent came under your control, not when it became a creature.

When a land becomes a creature, that doesn't count as having a creature enter. The permanent was already on the battlefield; it only changed its types. Abilities that trigger whenever a creature enters won't trigger.