Karamond the Devourer

At the beginning of your upkeep, sacrifice an
artifact and put a +1/+1 counters on Karamond
the Devourer.
Sacrifice an artifact: Put a +1/+1 counter on
Karamond the Devourer.
{t}, Remove any number of +1/+1 counters from
Karamond the Devourer: Add {c} for each
counter removed this way.