Levicorpus — The Prototype for Self-Levitation and Unsupported Flight
What if Levicorpus wasn’t meant to just suspend somebody in the air by the ankle, but was meant for auto-levitation, and revealed to be not perfected enough? What if Levicorpus was a failed innovation that led to the birth of another spell?
Think about it.
Levicorpus—that comes from "levitation" and "corpus" which means "body". This spell says "levitate the body".
Then, this spell focuses on the ankles. It turned out bad, and it seems to be Snape’s mistake in engineering Levicorpus, because the upper part of your body risks falling over (precisely what happens when you cast the spell), but the idea has some merit: I’m sure you’ve watched series where a character focuses their magical power on the feet to fly. It’s not like Mobilicorpus, which makes you whole body fly at an awkward angle and may not be appliable to oneself. If you want to fly, you might want to set a levitation spell on your ankles so you can "walk" in the air, and choosing the ankles might be a way to get more stability instead of the feet which you have to bend to walk.
And we know this is Snape who invented it, Snape, who had a friend capable of a bit of levitation as a kid (Lily) and who learns to fly at some point (DH). Wouldn’t he want to discover a way to fly like Lily did? A way to fly without brooms, him who seems to suck at it? Wouldn’t he want to impress people (Voldemort?) by showing how he invented a Charm to make yourself fly?
This sustains the theory that
1) Snape’s spell wasn’t meant to attack people (not even in self-defence!) but was just a way to impress and innovate,
2) Snape used it on himself for tests (or even animals, or dead animals etc, and the spell was stolen only because someone could have stolen his book for instance) because he wanted to fly and not make the others levitate,
3) the thoery that Snape is the one who taught Voldemort how to fly instead, after perfecting his spell.
NB:
We can wonder if Levicorpus derived from Mobilicorpus...
Much like Sectumsempra seems to derive from Rictumsempra.









