Need an early game challenge for your viking friends?
This one combines jumping and fighting challenge.

The tower has to be placed with infinite health or it will collapse.
It comes with 3 extra small towers for ranged mobs to make your way up a bit more difficult.

How I prepared this challenge:

I spawned the tower in the middle of the bay in meadows and raised the ground pillar to support it (it doesn't need any support since it's spawned with infinite health, but it looks better when it's not floating on the sea)
Then I spawned greydwarfs on smaller towers/pillars and gave them infinite health so they cannot be killed.
Finally i spawned Eikthyr on the top and gave him some extra HP boost to make the fight last longer than a minute - 2500 hp.

I also set up the rules for everyone willing to participate:
1. Only meadows foods
2. No armor
3. Only level 1 wooden club and wooden shield

There is a small Yuleklapp hidden on the top as a prize. I think I put Megingjord inside but you can replace it with anything you like. I think Megingjord is a perfect prize as the next step is black forest and a lot of mining.

If you want, you can also add wards so your viking friends cannot place a portal anywhere on the tower. However, I suggest to allow building portals because with these rules we had to go back to fix our wooden clubs 3-4 times. Or make 5 clubs each :)

Even with portals it will take somewhere between 30 minutes and an hour to complete this challenge.

Have fun!