I'm surprised nobody wrote about Cyndaquil and the other Johto starters. Come on, Pokemon Gold & Silver was released in 2000, and Everything2 was created from E1 in 1999. HOW DID THIS HAPPEN /rant
Cyndaquil (Japanese: ヒノアラシ, translit. Hinoarashi) is one of the Pokemon starters you can choose from in your Johto adventure. It has a National Pokedex number of #155. Quil's a fire type and has three stages in "evolution", just like Charmander (which has Charmeleon and Charizard). It evolves into Quilava when leveled up to at least level 14, which will evolve into Typhlosion starting at level 36.
Cyndaquil is small, bipedal, and looks like an echidna, with a bluish back and a cream-colored front. You will never see a Cyndaquil with its eyes "open". Think of it like Brock, but is a small Pokemon. Cyndaquil are easily intimidated (hence why in Pokemon Mystery Dungeon Red Rescue Team, when the game sees that you are timid, you become a Cyndaquil). If you scare them, provoke them to fight you, or make them happy, their back will erupt into flames (which is what you see in the official art, isn't that cute). Or they may just curl into a ball.
As with all other new Pokemon in the Johto Pokedex, Cyndaquil reappears in future core series games like Pokemon Ruby & Sapphire. Cyndaquil also appears in spin-offs like the Pokemon Mystery Dungeon series. In Gold, Silver, and Crystal, Cyndaquil is arguably the best starter to choose in Generation II (and IV for Pokemon HeartGold & SoulSilver), with Totodile being a close second. However, in Pokemon Mystery Dungeon Red Rescue Team, Cyndaquil is one of the worst starters, because the final evolution, Typhlosion, has no secondary type. Make Chikorita your partner, and you're gonna play the hardest difficulty of the game (Chikorita sucks).
The name "Cyndaquil" comes from the words cinder (ashes) and quill (needle-like hairs). Combine them, you get an idea of a Pokemon that has flames that look like needles as its hair. It's Japanese name Hinoarashi on the other hand, may come from 火 hi (fire) and ヤマアラシ yama-arashi (porcupine).
Here are its Pokedex entries from Gold (HeartGold), Silver (SoulSilver) and Crystal:
It is timid, and always curls itself up in a ball. If attacked, it flares up its back for protection. (Gold & HeartGold)
It usually stays hunched over. If it is angry or surprised, it shoots flames out of its back. (Silver & SoulSilver)
The fire that spouts from its back burns hottest when it is angry. The flaring flames intimidate foes. (Crystal)