Splitting Waves

Choose target creature. If that creature is untapped, tap it. It doesn't untap during it's controller's next untap step. Otherwise, return that creature to it's owner's hand.
An odd phenomenon happens in the Kalacres Sea. The sea usually splits into multiple "tears" to form these unusual, yet beautiful, chasm-like shapes. It usually ends horribly when these two ridges meet again, however.
-Ana, Horizon Fleet Helmsmage.