Vermithor, the Bronze Fury

Flying

Whenever Vermithor, the Bronze Fury deals combat damage to a player, roll a d20. When you
do, put X +1/+1 counters on each of up to two target creatures, where X is the result.

“The dragon named Vermithor is the largest in the world after Vhagar, and perhaps the most fierce.
He’s called the Bronze Fury.”
- Rhaenyra Targaryen