Achlyn is very similar to your everyday Sphinx in many ways, not so much in others. She enjoys ear scritches, balls of yarn, fish and giant laser lights. She's gentle, friendly, incredibly sweet.. when not rampaging through a village devouring every inhabitant. Lifes simple pleasures were the best for her, but she had a few issues that usually prevented her getting too rough with her 'toys'. Being taller than the largest mountains made life difficult in some ways for her, finding a mate was nearly impossible, finding a suitable meal even moreso; but thankfully the Gods gave her a few ways of dealing with that. Not only was she literally of titanic proportion, but they also gifted her with a control over magic, specificly Alteration magic. She can make things grow or shrink as she sees fit, including herself! It wasn't uncommon for the Sphinx to take on a much more accomodating size in order to slake certain thirsts.. but also to just not crush everything she came anywhere near with her constantly swaying tail! That tail never stopped moving, even when she slept! It has often been the source of jokes about how it might have a mind of its own.. and if only people knew the truth behind those words!
Along with being able to alter the size, her body is something of an oddity. She possesses both sexual organs, yet only one is active at any given time. She can alter which one of course, but judging from her appearance and choice in 'clothing' she definitely leans more towards the feminine aspects of her dual nature. She has no preference sexually in partners, but has been known to abduct certain males for months on end..
So how big is she exactly? The easiest method of measuring her, since there is no tape measure in the world large enough, is to compare her to landmarks. When on all fours, she stands as tall as the largest mountain in the Northern Hemisphere, which peaks at just about her bellybutton. With a single misstep, she could obliterate a city the size of New York along with half the surrounding hamlets. It's been rumored her breathing is what keeps the winds blowing, for she's long enough to if she stood sideways by an ocean; she stops the flow of wind enough to nearly still it entirely. A single fang is the size of a skyscraper, and the rough tongue behind them larger still. Her appetite is limitless, for her body also repairs itself incredibly quickly to keep up with the rigors of gravity and atmospheric pressure. To a human who tried to climb her, they would very likely freeze to death if not pass out due to lack of oxygen by the time they reached her chest. So to answer that question? Colossal