Shokki, the Coiling Furnace

Whenever you put a card on the bottom of your library, put a +1/+1 counter on Shokki, the Coiling Furnace.
If a spell or ability exiles one or more cards from the top of your library and allows you to play those cards, if you don't play one or more of them by the end of the phase or turn specified by that spell or ability, you may pay {1}. If you
do, put those cards on the bottom of your library