Chamber Sentry enters the battlefield with a +1/+1 counter on it for each color of mana spent to cast it.
, , Remove X +1/+1 counters from Chamber Sentry: It deals X damage to any target.
: Return Chamber Sentry from your graveyard to your hand.
At the beginning of your upkeep, exile a creature card from your graveyard. If you do, put a +1/+1 counter on Charnel Troll. Otherwise, sacrifice it.
, Discard a creature card: Put a +1/+1 counter on Charnel Troll.