It only lets you use either the turn the creature enters
As weird as it sounds, apparently the combo of using Thawing Glaciers to keep getting lands and then sacrificing those lands to gain life with Zuran Orb was simply too good
Some decks combine this strategy with cards that punish your opponent each time your creatures die (such as Blood Artist), and this has seen lots of success in winning decks
For the purposes of this discussion, though, I'm going to use Zoom, but Discord, Google Hangouts, and others work just as well
This also means you have cheap and easy ways to copy this spell with Dual Strike or Rootha, Mercurial Artist
Hei Bai, Forest Guardian Hei Bai, Forest Guardian helps you get to the wide spread of shrines you want by tutoring for one