Attempt 1 at a mechanic to represent praying. Perhaps there's too much repeatable self-mill. That would set-up for turning the gods on if I continue with that route ((( Mishar-Rahsim, Hunting Twin t2))). A tap cost, like outlast would probably fix this, now included. Can the activation order go tapping the creature, then paying mana or is that off the table (for some reason I like the flavor of tapping first). No, that'd probably mess with player's expectations.

Cost aside, I'm not sure what the reward would be. This concept was simply "pay 1 mana for a 2 mana spell." A number of variable could be created, but some would look ugly and be impractical (ex: Prayer (mana)- Toughness 6). By making the prayer an exact rather than something of less (this must be CMC 2 not CMC 2 or less), limits the practicality of such a mechanic since it sounds sucky without any library manipulation going on. No, this idea probably won't work as a mechanic.

The templating here is pretty painful, but I think it can be salvaged. How about you make it a keyword action:

> , : Pray for converted mana cost 2. (Reveal the top card of your library. If it has converted mana cost 2, you may cast it without paying its mana cost. Otherwise exile it.)

With the specific criteria (i.e. CMC 2, not CMC <= 2), this would work better on artifacts or small creatures like this. Players won't want to tap their bigger creatures (and/or pay more mana) on an unknown risk like that.