Given the fact that Drogo’s wound festered under the black magic of Mirri Maz Duur, a potentially poisoned arrow would be an excellent callback to the character, as well as terribly unfortunate for the struggling Khaleesi.
Could this be how one of Dany’s mightiest dragons meets his end?
That’s an excellent question, as Game of Thrones fans know, Qyburn is more than capable of concocting some nasty poisons that can be placed on the tip of an arrow and, given that the siege weapon is his pet project, it doesn’t seem impossible he may have thought to lace the arrows with something.