Shang-Chi, Martial Mentor - Legendary

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.
Power-up — {5}{G}{G}: Put three +1/+1 counters on Shang-Chi. (Activate each power-up ability only once. Reduce the cost by his mana cost if he entered this turn.)