Wow. Better one-drop acceleration than Arbor Elf... at the cost of giving your opponent a little mana too. It's unfortunate that this can target your opponent's untapped lands, though of course she can tap them in response. But you can't say "target tapped land" because that'd make the ability unable to be activated if any one opponent has all their lands untapped.

I think this might be very, very good. But that's fine; having some Shabti playable is a good thing :)