IJN Hakuryuu

Trample

At the beginning of your upkeep, sacrifice a
creature. If you can't, put a -1/-1 counter on IJN
Hakuryuu.

Whenever IJN Hakuryuu attacks, if it has one or
more -1/-1 counters on it, it gets +2/+2 until end of
turn for each -1/-1 counter on it.