Hypo Crested Geckos
Because the Hypo gene removes dark pigment from a crested gecko, a yellow will fade toward cream, a red becomes pink or neon, and a black base turns lavender. You should judge the gecko in front of you instead of the label because the effect varies a lot between animals.
About the Hypo gene
A crested gecko has less melanin with the Hypo gene. The look of this depends on the base colour underneath. A yellow base creates the pale creams sold as C2, while a red base results in pinks and neon reds. A black base produces the lavender animals. Keepers buy it for the lighter, cleaner base tones and because several named colour morphs are built on it.
Appearance
The hypo trait produces lavender on a black base, which can range from purple to pale grey or, in rare cases, sky blue. If the base is red, it removes the black and brown to leave pink or neon reds, with tails that have more even colour and no dark pigment like a normal red. On a yellow base, or for any animal with little dark pigment already, the result goes from a unicolour white cream to pale yellow, and the usual dark spots on the kneecaps and under the tail base fade noticeably. Rather than orange, hypo animals tend to have white or cream patterns. These tones shift to peach and silver with Phantom. How strong the effect is varies a great deal from one gecko to the next based on what other traits the animal carries and how refined the line is. A hypo that shows the trait strongly is one that barely changes colour when it fires up.
Genetics
Hypo is a dominant trait that does not always show fully. Because its forms act more like incomplete dominants, two hypos can look very different. You should ask the seller what a Super Hypo means since that same name also describes the leucistic super of Fire, which is a separate gene. Lavender is a black base animal with hypo. Cold Fusion is a refined type of hypo that brings blue tones to black and red bases, and Creamsicle is also built on hypo. This trait was in collections from the start. A cream-on-cream line from AC Reptiles showed it early, in 2004, and Tom Favazza of Geckological began naming and describing hypo around 2015.