While Stiles and Scott are at the vet getting the black dust, the vet puts the mountain ash on the table and says it's for Stiles. Stiles picks up the bottle and it's in his hand. A shot later the bottle of ash is back on the table, but Stiles never put it down. Then the shot after they show it on the table, it's back in Stiles' hand and he sets it back down.
This is Colton Haynes' third time playing a supernatural creature. He was a Werewolf in "The Gates" and a Jackal in "Nine Lives of Cloe King."