You can crawl or swim in the sky in creative mode by changing your gamemode from spectator while under blocks

Im swimming in air, Ofc im flying because im in creative. But normally you can't swim in the air..

What I expected to happen was...:
Just me stand up like im flying in creative

What actually happened was...:
Me in swimming mode..

Steps to Reproduce:
1. Go in spectator mode and then you need to be in the perfect place to active this.. Idk how I perfectly did this..
2. Go back in creative, and under a slab..
3. You're now swimming in air!