For some reason, when lined up correctly, it's possible to enter a sideways pipe from above, skipping the pipe entrance animation. By corner clipping against the ceiling, the cat is pushed into the exact correct position, where he can fall down into the pipe. This likely won't be done in RTA as it seems to only save around a quarter of a second and it's very easy to fail, but it still brings us closer to a potential sub-3 warpless.

Interesting find! What were you trying to do when you found this?

I've known about variants of the instant pipe glitch before - the same thing can be done at the start of level 2 at the first sideways pipe by hitting the right side of the left hidden block, so I was messing around with that with the pipe in the video and managed to pull that off.