Drumstick first appears to Spot after she makes a wish on a four-leaf clover to make her a Dalmatian.
Their arrival featured the egg, they teleport in, crashing into Hiccup Hole. As they emerge in a ball of light, the light short circuits and Drumstick comments it's the last time he buys used. He then introduces himself to Spot and tries to grant her wish, by turning her into a carnation. When Spot comments that's not what she wanted, Drumstick tries other mishearings before getting it right.
When Spot becomes a dog, Drumstick explains what changes there are from being a dog before giving the caution: "Don't fall asleep in the driveway."
When the Pups are later captured in the pound, Drumstick appears by crashing his egg through the wall, commenting he needs to get his brakes checked, before turning Spot back into a chicken (but not before the "equation," "graduation," "vegetation," and "carnation" alter egos), and then she happily expresses pride in having feathers, a beak, and only two feet instead of four. He bids farewell to Spot, saying he'll see her next wish and flies away. The pups escaping through the hole he made in the wall, unknown to Spot, who was attempting to unlock the door, like she planned first.