When Dowsing Dagger enters the battlefield, target opponent creates two 0/2 green Plant creature tokens with defender.
Equipped creature gets +2/+1.
Whenever equipped creature deals combat damage to a player, you may transform Dowsing Dagger.
For more information on double-faced cards, see the Ixalan mechanics article (http://magic.wizards.com/en/articles/archive/feature/ixalan-mechanics).
Attacking with an equipped creature doesn’t cause Equipment attached to it to become tapped. Dowsing Dagger will normally be untapped when it transforms into Lost Vale.