The Axolotl is a type of salamander from Mexico that does not metamorphosize into a grown up shape instead it reaches sexual maturity in its larval form. This is called neoteny. In fact axolotls can be forced to develop into an adult terrestrial salamander by injecting them with thyroid hormones.
Axolotls are used in scientific research as a model organism for vertebrate development because of the large size of their embryo. Axolotls are also the subject of many studies on how salamanders regenerate lost body parts.
Many people like to keep axolotls as pets. There are some albino varieties, some with an interesting golden coloration.