In the webcomic Sluggy Freelance, Aylee is an alien from an alternate future. Her species is extremely adaptable; every so often, when her environment changes, she will metamorphosize into a form better suited to the current circumstances. The change takes anywhere from seconds to months.
Aylee was brought to the present timeline when Torg and Riff started experimenting with the dimensional flux agitator, finding themselves on a futuristic starship. A menacing Gigeresque xenomorph attacked, ate the entire crew, and chased the boys home through their return portal. It showed up back in their apartment, but they drove it off using laser cannons acquired from the starship's armory.
Finding it difficult to survive in our dimension with no marketable skills and no photo ID, the alien soon returned to Torg and begged for a job. Since she also coincidentally saved him from a fate worse than death, he agreed, and employed her as a secretary for his web design business. This worked out rather well, because Aylee (as she now called herself) was pleasant on the phones, and could type 75 WPM. The downside: it took her a while to learn not to eat the clients.
When Aylee's metamorphic nature first manifested, she made several changes in rapid succession, as her metabolism attempted to make sense of the new environment. First, she changed into a well-endowed female humanoid. ("You realize, despite the scales and stuff, she's technically naked.") That was almost immediately followed by a winged little gnome who looked like The Great Gazoo, a reptilian version of Bun-Bun, a generic dinosaur, a weird beastie with four arms and a duck bill, and apparently other short-lived forms we didn't get to see. Aylee then wrapped herself in a cocoon and left a note saying she felt a "big change" coming on.
Upon emerging several months later, she looked like a cute puppy-snake thingy... but there was a surprise. Whenever she got nervous or tensed her muscles, she extended huge claws, fangs, and lots of sharp spikes from her body. This tended to unnerve people (especially Riff), but because of the wide frill that unfolded from her neck, she thought she looked like a pretty flower. At this stage she still ate people very often, partly due to the influence of Percy the cloned man-eating mammoth.
On January 1, 2000, Aylee began to transform again, into a form that could resist the nanite "Y2K bug" infection. The new form looked like a giant lima bean with a tail, but could unfold into a beautiful winged serpent. The act of unfolding also emitted an electromagnetic pulse, suitable for frying the dangerous nanites, plus every other electronic device nearby. The EMP and flight consumed a lot of energy, so she could only unfold for a short time, after eating a large meal. (Luckily for the human population this form no longer had any appetite for meat, and could consume only potatoes.)
When the human characters returned from their adventure in the punyverse, in August 2001, they found a new Aylee form. This one was a huge, terrifying, man-eating crab monster, complete with paralyzing venom and impenetrable armor. She had become the perfect cutthroat CEO of "Torg & Alien Web Design", and renamed the business to AyleeOrgNet.Com. This form was again carnivorous, and made a habit of dining on her own employees.
But! The Crab Monster was actually an evil clone created by Hereti-Corp. The real Aylee had been kidnapped during metamorphosis, and placed in a cryogenic capsule. Her body reacted to the cold by generating lots of heat, so her newest form is that of a small red dragon. She fuels the fire by eating all the time, and can consume anything, though by choice she no longer eats people.
As of March 2004, Aylee remains in the dragon form. There's no telling how long it will be before the next time she morphs.