Dragon babies are born with soft scales and flexible frills, no claws and no wings. As they age their frills harden into horns, and they begin to develop environmentally influenced traits. For other dragons this could mean a lengthening of the body into a more snake like form, or ice spikes for protection in the tundra. Spike developed magical traits that couldn’t be seen, so he appeared to change little. As he grew he gained glowing magical runes around his body, and neon green freckles. He is also able to read and write, a somewhat unique talent. Dragons aren’t stupid, but their society in the Dragonlands doesn’t consider literacy important.
Spike currently has crooked and jagged teeth, because he’s beginning to lose his baby teeth! He also has normal claws along with a poisonous claw on each of his wings. His venom disrupts the flow of magic in the location it wounds, and has no anti venom. He tries not to use his poison. His tail tip is thick and blade-like, handy for prying gems from stone.
Spike lives with the Apple family, who he’s closest to. His relationship with Twilight is dwindling as she pushes him away. He’s friendly with Pinkie Pie, estranged from Fluttershy, awkwardly friends with Rarity, and hasn’t seen Rainbow Dash in person in quite some time.