Next up in the Terraria boss concepts, the Beast.
One of my favorite boss battles in recent history was with the juggernaut of Monster Hunter Tri, Jhen Moran. And I always loved the idea of having to actually 'board' a creature in order to defeat it. Hence the Beast!
Definitely an endgame scenario. Not only do you have to worry about him submerging into lava while you're on top of him, his magma rock attacks, and the attacks of the imps he summons (with a terrible screech) around him, but you can't even hurt the damn thing until you open up a section of its body with a pick. (And only Nightmare or above works.)
The rewards, of course, would have to be very high. I thought an Obsidian armor set would look very neat, but the real prize would be crafting a scythe weapon.
Yes, yes. Scythes are one of the most impractical, overused, cliché not-even-really-a-weapons of all time. And you know what. I freaking love 'em. So DEAL I SAY, DEAL.