Gollux

Which in turn clearly are rip-offs of Jr. Balrog.
Infact, every dang mob is just rehashes of the Snail with minor changes.

Actually, I just pulled a bit of imagination, and thought of some ideas.

-Side scrolling boss, chasing everyone slowly, with platforms and traps appearing along. When the boss timer runs out, the map ends on a cliff and you fall if you don't kill him on time. A giant slug/slime on a tunnel could do the trick, pushing anyone touching it / going past a certain point. You can't go forward too much, either, there's a restriction on both sides. (the map isn't generated, it's just timed so when you reach the end, the timer ends by synching it. The longer you survive, the harder the map gets)

-Climbing boss, the same as last one, but vertically, on a tower sinking in lava, while fighting a demonic bird attacking you flying. When the timer runs out, the tower ends, getting you to meet your slowly approaching doom while the boss keeps flying away. (the map isn't generated, it's just timed so when you reach the end, the timer ends by synching it. The longer you survive, the harder the map gets)

-Hivemind boss, a boss that is something like Dimension invasion, but in a single stage. It could easily be shadows emerging from a portal. If too many shadows are in the map (filling a shadow gauge), they sucessfully corrupt the map, and you loose, "teleporting" you to a black map that instantly kills you. Difficulty would grow bigger as it goes on, with more and more variations coming out. Things like Swarmers, that spawn very commonly (And can even be knocked back easily), filling that gauge fast, but they are easy to kill, Bombers that explode dealing massive damage if not killed fast enough (so single target attacks are very useful still), Juggernauts, with a lot of health, Cursers that inflict status changes, Shielders that make every shadow immune until they are killed, Challengers, that can only be damaged by one person in particular from the expedition each, and lastly, the Corrupted Entity that is generating them himself, after you brought down enough of his shadows. Kickass notice and animation when it spawns to know pomegranate's going down.

-Coward hunt: It's almost a pq, but also a boss fight. Imagine a haunted mansion, mine or something. Now that you hunt a ghost in there. The ghost begins to fight, but after you took down like, 20% of his hp, he flees to heal. Now you have to find him before he heals too much. If you are fast enough hunting him, you can bring him down in 6 assaults. Every time someone finds the ghost, everyone gets a notice and gets teleported to his map in 5 seconds. Then the battle continues. Every time he fless, he sets traps on the rooms again, to make him harder to find. Find a good balance between hp and time to find, and you have an interesting boss.

So yeah... Now that I think of it, there's a LOT of room for originality.

Nexon, if you read this post, you have 100% my permission to use this :p