Otto, Aberrant Shapeshifter

Changeling (This card is every creature type.)
Whenever Otto, Aberrant Shapeshifter is dealt
damage, it gains that many Rage counters. At the
beginning of your upkeep, remove 2 Rage
counters.
If Otto, Aberrant Shapeshifter has one or more
Rage counters at the end of your end step, until
the start of your next end step, its base power
and toughness become 5/5, it gains trample,
and must attack each turn if able.