Spike

Spike is a purple and green baby dragon who is Twilight Sparkle's assistant and only means of contacting Princess Celestia in My Little Pony: Friendship is Magic.

Personality
Spike is a bit of a sarcastic dragon and laughs at others' misfortune. However, he is very supportive towards Twilight and also helpful. Though protective of his masculinity and often dismissive of things he considers 'girly' he is often seen being just as enthusiastic about them as any of the others. He can be a bit insecure, and protective of his role as Twilight's "Number One Assistant."

One trait that has grown over the course of the series is his enjoyment of announcing. He first got into it during Fall Weather Friends where he announced the Iron Pony Competition, and later got quite disheartened when Pinkie Pie was set up as the announcer for the Running of the Leaves (and likewise, was obviously enthusiastic when she asked him to be her co-announcer). He continues this role in Suited For Success, where he emcees Rarity's fashion show.

Skills
Spike has the ability to transport scrolls back and forth between Twilight Sparkle and Princess Celestia. He sends notes by breathing magic fire onto them and blowing them into the breeze. He can also send multiple notes at one time, as seen in Griffon the Brush Off. He receives scrolls by belching them up (also, as shown in The Ticket Master, Spike is also able to transport other objects, example being the tickets for the gala).

This ability appears to be deliberate as opposed to instinctive; when not specifically using his fire to send notes or items to the Princess, he breathes "regular" fire which burns up items, like the book he accidetally burns in Owl's Well That Ends Well. In Over a Barrel, he breathes fire for the purpose of roasting food. He appears to have no control over recieving messages, however; when the Princess sends a message, he belches it up whether he wants to or not. Some fans humorously refer to this ability as "Hot Mail"; referencing both the commonly used e-mail program and Spike's unique method of sending messages to the Princess.

During the episode A Dog and Pony Show, Spike digs up gems for Rarity. He uses several different techniques, including a dog- or mole-like scrabbling at the ground with his hands, using the splay of his tail as a shovel, and bouncing on his tail like a jackhammer. The effort doesn't seem to tire him in the least.

He plays the piano for Pinkie Pie's musical number in Over a Barrel.

Spike possesses an iron stomach and is omnivorous in the truest sense of the word. Gemstones are his most favorite food, though he has also been seen eating grass, hay, and even muffins dug up from trash that had previously poisoned half of the town, in Applebuck Season.

Relationships

 * Twilight Sparkle - Although Spike is ostensibly Twilight Sparkle's assistant, he at times takes on the role of baby brother or adviser. He's never shy about pointing out her failings, often with sarcasm and jokes, however the two share a sincere affection and he is always ready to support her when she gets in real trouble. It's also worth noting that the two have known each other since the moment Spike was hatched, as shown in the The Cutie Mark Chronicles.
 * Rarity - Spike developed a crush on Rarity the moment he saw her and sometimes goes to great lengths for her attention. In Green Isn't Your Color, he gladly offers his body as a pincushion for Rarity to use while designing a dress. In Boast Busters, he tries to impress her with a mustache conjured through Twilight's magic, however this attempt met with little success. Spike thinks that maybe the mustache wasn't enough and considers adding a beard too. His utter adoration of Rarity is practically unnoticed by her.
 * Fluttershy - After an awkward first conversation with Twilight, Fluttershy sees Spike and her timidity almost immediately vanishes and is replaced with utter fascination over him. As she has never seen a talking baby dragon before, she requests to learn everything about him, and Spike proceeds to tell her his whole life story.
 * Pinkie Pie - Spike is often shown reacting positively to Pinkie Pie, if only because he seems to find Twilight's annoyance with her amusing. During Fall Weather Friends the two share announcing duties, where Spike obviously struggles to keep up with her rather odd commentary. He also helps her out in Over a Barrel, playing the piano during her song. In Party of One, Pinkie's bizarre nature strikes fear into Spike when the former, under the false impression that her friends are avoiding her aggressively interrogates Spike to find out why they are seemingly ignoring her. Fortunately, Pinkie's spirits are uplifted later when it's found that her friends were throwing a surprise party for her and Spike seemed to quickly forget Pinkie's moment of madness, casually feasting on the gems she promised him if he talked.
 * Applejack - Spike and Applejack regularly have a dismissive attitude towards each other especially noted by the fact that they don't share much spoken dialogue. Although tension is unfelt between them, Applejack appears to be fond of him, alongside Spike's childlike nature.

Appearances
Spike appears in most episodes with exception of episodes 8, 12, 16 and 17.

Trivia

 * Spike's appearance is literally based on his Generation 1 incarnation rather than his Generation 3 incarnation. But it has some few modifications done by Lauren Faust herself. He is also the second of the main cast who was part of the original My Little Pony cast. This is because Hasbro lost the rights to nearly all of the original character names, with the exception of Applejack and Spike.
 * Fluttershy calls Spike a "baby" dragon in Friendship is Magic, part 1, and later it's shown in The Cutie Mark Chronicles that Spike was hatched from a dragon egg by Twilight when she was a child, which makes him a few years younger than her. Coupled with the hundred-year nap of the dragon in Dragonshy, it's evident that dragons mature very slowly and may possibly live for thousands of years.