Spike

A dragon hatched by Twilight during her entrance exam to Celestia's School for Gifted Unicorns. He helps Twilight run Ponyville's library, where she often refers to him as her "Number One Assistant".

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Spike can send mail through his flames because of the Magic that Twilight Sparkle infused in him when she broke his egg.

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Princess Celestia gave Spike to Twilight Sparkle as an experiment to see if a Dragon can be raised in a Ponies society.

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Spike is the only known tame Dragon.

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Spike will grow wings when he gets older.

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Twilight Sparkle made Spike return Peewee after she decided that he was too much trouble.

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