An entire world made of nothing but jelly? Pah! Madness! No such place! Certainly not talked about since Year 4!
Well... if there was such a place, which there certainly isn't, it would be a place constructed entirely of jelly, including the buildings.
Hypothetically, Jelly World would be nestled in mountains, the exact location unknown; though lava tracts would run between the mountains, which would suggest it was near Tyrannia. The actual ground of the city would be made of jelly, and as a result would be quite bouncy.
Here's how Jelly World would have changed over the years, had it actually existed. Click on the thumbnails to view larger snapshots.
Presumably, an entire world of jelly would be a reasonable temperature, but would neither be too warm nor too wet, as either would melt the jelly.
As of course there is no Jelly World, there is no one to rule Jelly World.
People who incorrectly maintain that there is in fact a Jelly World often state that at one time in Neopia's history in Year 5, every single Petpet on the planet disappeared. They were later found eating a Giant Green Jelly in Jelly World. Once they had their fill, they left and returned to their owners. Of course, such talk is completely without merit.
In Year 15, a new timeline for Neopia was created in which a place called Wobbleshire was discovered. It is unknown if this was a location within Jelly World, or a new name for Jelly World itself. Either way, the timeline was restored to normal, and Wobbleshire was never really discovered.
I think, to be honest, in a world where your home, furniture, and even yourself could at any moment be eaten by a passing tourist, that the state of the economy is the least of your worries. Perhaps exporting jelly across the planet would take your mind off your impending doom?
Jelly, I imagine that's what they'd eat in Jelly World, if it existed. Which it doesn't. All types of jelly and flavours. If you got bored of jelly shaped jelly... why, you could eat the building you were sitting in.
Jelly jelly everywhere, but not a drop to drink.
As of course it doesn't exist, no one could ever invade Jelly World, so there's no need for it to have an army. Speaking in a purely theoretical sense, anyone invading such a world would be stunned by the utter bizarreness of the place that any thoughts of violence that may have been in their heads would quickly evaporate.
If you were planning on visiting a place that doesn't exist, you might be able to visit the following places, which also don't exist:
... But of course, as we all know, it isn't real.