Chubbz's Decoder

When this enters the battlefield, you may pay X
life. If you do, put that many Decoder counters on Chubbz's Decoder. If you don't, put half of X
Decoder counters on Chubbz's Decoder instead.
While there is a Decoder counter on Chubbz's Decoder, it can not gain counters of any type.
At the beginning of your upkeep remove a Decoder counter from Chubbz's Decoder. If you do, proliferate.