A mostly working wormhole for those interested. I'm going through and trying to understand how they work, so I cleared out Gato's event and placed only a wormhole in the area. It takes you to Enhasa. Other events have the individual characters doing special animations while the portal closes, but I sort of changed this one to just make the sprites dissapear before it closes. Right now, it just hides Crono's sprite, but I'm sure it can be made to do the same for the other characters, and it shouldn't be to hard to just drop in some animations for them before the wormhole closes. The wormhole takes up about 3 objects in the event, 09 0A 0B. These can be copied and pasted to other events with minimal changes to them needed (x,y coords, etc).
Perhaps others could post here about making it better, and a tutorial for a customizable wormhole could be added to the site.
Apply to an unheadered ROM, and enter (you guessed it) Gato's section of the fair.
http://www.geocities.com/chickenlump/wormy.zip