Champion of the Hareish - Mystery Booster 2

Buddy list (As this creature enters, if any of its creature types isn't on your buddy list, write one of them on your buddy list.)

Whenever another creature enters the battlefield under your control, put a +1/+1 counter on Champion of the Hareish if one of that creature's creature types is on your buddy list. Otherwise, write one of its creature types on your buddy list.