He is the main enemy of Alpha and the primary antagonist in "Alpha's Egg".
In the episode
Dragonfly, along with Alpha, are first seen as hatchlings who grow to despise each other as they mature. He is the eldest of his siblings and, due to his short attention span and distraction towards dragonflies, has been nicknamed so.
To teach him to hunt, Dragonfly's parents attack a herd of Saltasaurus (Alpha being one of the babies in the herd). They confront the adult Saltasaurs, but Dragonfly alerts his mother to the saltasaur calves. She turns her head, spots them and directs their assault on the calves, devouring three of them. As the adult Aucasaurs and the young females pass by, Alpha comes face-to-face with Dragonfly (this is their first encounter). Luckily, a dragonfly flies by and Dragonfly starts to chase it, and Alpha survives.As Alpha enters adolescence, she meets Dragonfly again, this time in the wildlands. While Alpha and her herd head for a forest to eat, Dragonfly and his family are right behind them. Dragonfly eagerly darts towards Alpha. She startles him with a bellowing growl, and he jumps away. The Aucasaur pack trots ahead. As Alpha browses from a tree, another female Saltasaurus comes forward and angrily shoves her aside to eat the leaves, but stumbles on a log, and tumbles down a hill, breaking bones. Alerted by the cow's screams of pain and torment, the Aucasaurus pack heads over to her and kills the wounded animal, with one Aucasaur piercing the Saltasaur's jugular. As they eat, Dragonfly slams his thigh into one of his sisters, but his father scolds him for this action and his rude behavior. The pack continues to eat. A while later, Dragonfly wakes up from a good nap, gets to his feet and heads off to look for a mate to start a pack with, since he knows that as long as he stays, he'll end up being scolded by his father.
Later, he finds a female Aucasaur around his age and attempts to seduce her by inflating his throat pouch, but she at first refuses. However, his persistence and inflating of his throat pouch finally win her heart, and they become mates.In the end, Alpha looks for a spot to eat, she senses Dragonfly and his mate in her presence and readies herself for a duel with them. Dragonfly bares his teeth and goes for an attack. Alpha headbutts him, whips the female Aucasaurus with her tail, and then rams Dragonfly, disorienting him for a shot time. He wakes up from his disorientation and clamps his jaws on Alpha's left shoulder, but he loses his grip and slams his head on the ground. Alpha falls and crushes Dragonfly's skull under her weight. Alpha then rises to her feet, stares at Dragonfly's lifeless corpse and walks away, having won the duel. The Aucasaur female rises to her feet, having just witnessed the whole thing, and tries to wake Dragonfly up. To her horror, her attempts to awaken Dragonfly fail miserably, and this causes her to throw her head backwards and let loose a loud, mournful howl.