and uhc is?

Ok, let me explain in more depth about uhc. UHC also known as Ultra Hardcore in which players or teams need to gather materiels and they have a certain amount of time to gather them. After getting resources  and all when the timer is up it teleports you to the mid ( coords 0,0)
The point is to kill the others if you're alone or in teams which you'll try to kill the other teams and survive. Survive and be the last standing team.

UHC can last about 1 - 2 hours each so you'll have time to gather all materials and be prepared to attack the other teams.

UHC as you can see it's hardcore so you won't normally regen health by getting a full hunger bar but you'll have to make golden apples, notch apples, potions of regen or heath, some servers even have golden heads.

UHC will have a hub where you can select the lobby you want usually there are a lot in which you can choose between lobbies where you're alone, teams of 2 or even teams of 4.

In my opinion uhc is among all the games I've ever experienced the most fun game ever except survival games ofc.
It's a true battle between other teams which is spectacular if you have a diamond sword or enchanted armor, I'll guarantee you that you won't die except if you're AFK during the final battle.

Other information:
There is a timer for everything such as making your teams, if you don't have a team by the time where the timer go off well the server kicks you... which is harsh but it's the way it is.

So like I said you have 1 - 2 hours to gather materials and get yourself some armour because you'll need it.

Example if your game is for about 1:30 and the timer is at 5 minutes left, the server or a reminder will state in how many minutes you'll get teleported or you'll have to walk your way to the coords 0,0.
When that timer is up it will be forced to teleport you and your team (if you have one) to the mid, in which you'll have a big battle against the teams who have survived.

if you win, well you win nothing YAY!! but I would like if you put some prize for winning.

that's sounds cool, when I play it we start in random areas in a randomly generated terrain, without ocean though. And you fight when you meet each other which could be at any time. your way sounds cool too though, I think both ways are a lot of fun. My way is the original way made by the mindcrack server

Mindcrack - Ultra Hardcore - S15E1 - Here we go!

this is my way of playing UHC, I like to play like this with friends and stuffs

we would obviously have to modify the rules and make a bigger/smaller map to suit our needs