Wormholes with path tracing

For the video after my next one, I started rendering wormholes. And I rendered this wormhole with path tracing. Have you ever seen wormholes before? Usually, in renders, they point to different universes. But you know me: I couldn't let that happen, so my wormholes point to the same universe, and you can see both ends of the wormhole in the same place.

Wormholes are usually represented as bent space, so to make both ends exist in the same universe at arbitrary locations, I came up with a smart trick :P

The next video is just 6s long, but it took 2h to render...

And here are caustics from a wormhole, rendered with ~10k samples: