Dryad Arbor

If a Dryad Arbor gains flash, or you have the ability to play Dryad Arbor as though it had flash (due to Teferi, Mage of Zhalfir or Scout's Warning, for example), 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 Dryad Arbor during another player's turn, and you can't play Dryad Arbor if you don't have any land plays remaining.

Forest is a land type and Dryad is a creature type.

Dryad Arbor 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.