This dinosaur doesn't know what will kill him, but he's determined it won't be heart disease.

Resolute Veggiesaur

Trample
Whenever you roll your third die each turn, put a +1/+1 counter on this creature.

Unfinity

If you roll multiple dice at the same time, and one of them is your third die roll that turn, Resolute Veggiesaur’s ability will trigger. It’s not necessary (or, in some cases, possible) to identify which roll was the third.

Remember that if a die is rerolled, that counts only as a single roll. The original roll doesn’t count. Similarly, any die roll that’s ignored doesn’t count.