This is real. See for yourself. Follow the instructions on the text given. If you didn't catch it, here it is. Seed: -1552931850556355815
z:-245 c:16 (11)
f: 3 (EAST)
If you follow the x, y and z, you will find lava. Put it out and pass the dungeon by going into a huge hole in the wall. Move forward until you see a chest on your right filled with lapis, 4 diamonds and, I think, other stuff.