Rain of the Stars

Target up to 5 basic basic plains or forests you
control. Target lands may be tapped for {g}{w} as a mana source. If you do so, extort them.
(They do not untap during their controllers next untap
step.)
"And then we saw a living star fly overhead and lay
its blessing on the grass below our feet. From that day
on, these lands have kept the shadow at bay."
—Aegis Fields fairytale