The boss spawner do give clues, but in case of Bonemass it's a bit on the vague side. I had completely forgotten about the bones until I had literally tried EVERYTHING that dropped in the swamps, except, of course, the bones. :P

Also, portals are a thing. You ALWAYS have the materials for a portal on you.

Edit: Punctuation is also a thing. I tend not to read a wall of text without any punctuation, because it is REALLY hard to read.