Encircling Fissure

If the non-awaken part of the spell requires a target, you must choose a legal target. You can’t cast the spell if you can’t choose a legal target for each instance of the word “target” (though you only need a legal target for the awaken ability if you’re casting the spell for its awaken cost).

The land will retain any other types, subtypes, or supertypes it previously had. It will also retain any mana abilities it had as a result of those subtypes. For example, a Forest that’s turned into a creature this way can still be tapped for green mana .

If the non-awaken part of the spell doesn’t require a target and you cast the spell for its awaken cost, then the spell won’t resolve if the target land you control becomes illegal before the spell resolves (such as due to being destroyed in response to the spell being cast).