Mauler, Automaton Soldier

{2}: Put an upgrade counter on Mauler if he
has none. Progress.
{3}: Put an upgrade counter on Mauler if he
has one. Progress.
{4}: Put an upgrade counter on Mauler if he
has two. Progress.
As long as Mauler has 3 or more upgrade counters, it has trample, vigilance, and indestructible.