Temporal Trenches
Enchantment
Whenever a creature enters, it phases out.
"Trust me: falling into another timeline won't keep us from getting back to ours. But it sure as heck will take awhile to do so."

I like it! It has a weird mix of consequences, preventing new creatures from blocking, but also protecting them from removal.

Reminds me of Teferi's Veil, which is a fun way to protect your creatures in a deck that attacks a lot.

It also reminds me of the stealth lane or whatever it was called from The Elder Scrolls: Legends, if anyone remembers that game.

I love this, and not just because of what it could do with Sands of Time or a pre-existing Disciple of Caelus Nin.