I added a Nether mod to minetest, and finally succeeded in building an obsidian portal. The minute I stepped through I was nearly engulfed in lava. I had to run away and come back with enough stone to wall off the lava flow and give me some clearance.

Once I started laying out some torches, I saw the shadow of an extremely long legged creature easily four times as high as me wandering in the distance.

Nope'd the fuck out of there as fast as I could.