Zabu, The Iron Minotaur

Trample, haste
Pay 5 life: Monstrosity 2 (If this permanent isn't monstrous, put two +1/+1 counters on it and it
becomes monstrous.)
As long as Zabu is monstrous, whenever it
attacks it becomes indestructible and gains
"Whenever Zabu deals combat damage, if
it is the first combat phase each turn, there is an additional combat phase this turn."