Wrenn is a planeswalker type, not a land type.

Due to its color indicator (appearing to the left of its type line), Wrenn and One is green. Color indicators apply in all zones, not just the battlefield.

Wrenn and One is played as a land. It doesn’t use the stack, it’s not a spell, it can’t be responded to, it has no mana cost, and it counts as your land play for the turn.

If Wrenn and One is changed into a basic land type, it continues to be a green Wrenn planeswalker, but it will lose its other abilities.

If Wrenn and One gains flash, or you have the ability to play Wrenn and One as though it had flash, you can ignore the normal timing rules for when during your turn you can play a land, but not any other restrictions. You can’t play Wrenn and One during another player’s turn, and you can’t play Wrenn and One if you don’t have any land plays remaining.

Playtest cards aren’t legal for play in any tournament format other than Mystery Booster Limited formats. On the other hand, we expect they will spice up a wide variety of non-tournament games (as long as everyone’s on the same page about using them!).

Playtest cards use a modified version of game symbols, such as {T} and {W}. These modified symbols should be treated as the standard symbols during play.

For many playtest cards, you’ll need to make a generous assumption that basic game rules would be updated to allow them to work. The Mystery Booster 2 Playtest Card Notes section (reproduced here in individual Gatherer rulings) provides guidance for fitting these cards into the existing rules structure.