I think spiral knights should have mid-bosses. And if you don't know what a mid-boss is, it's basically the same level of the Snarbolox(except Dante Inferno, being tier 2). Here are some I've thought of:
-Dante Inferno
Description: Son of Vanaduke, Prince of Fire. A lot like his father, though he is more mobile and aggressive. He summons weaker minions but more so they have strength in numbers.
The Fiery Abyss: a Hot Topic. (made up)
-Prince Sour
Description: Son of Royal Jelly with same abilities only weaker. According to the wiki, he would be the only Jelly allowed to have poison powers. He can send in green giants to spawn but cannot himself. Also he would be accompanied by Caustic Polyps.
Location: The Poison Bog. (Made up)
-Princess Bolt
Description: Unlike the rest of the family she is a Lichen like jelly. With the ability to spawn Quicksilvers and shoot lightning, she is a tough opponent to defeat with elemental weapons. Instead of dying like the other Jelly bosses, she surrenders and allows you to have all her drops. In a different mission, she is more powerful but has no minions. He also as abilities similar to blast cubes and oiler lichen. Master of Fire, when you defeat her she has more and different drops.
Location: The Princess' Quarters (1st time) Field of Fire (2nd time) (Both made up)
-Smashasourus Wrecks
Description: This is something I think should be at the Rescue Camp: a training hall. There would be dinosaur like robots to train with. My point is they're gremlin crafted and go on the fritz. The Biggest, Smashasourus Wrecks, would be the one you train against as a fake boss. You'd have to fight him again, for real though.
Location: Beginning Training Hall (made up, I think)
I'm speechless. Basically all you did was take the bosses, put a label on them as son or daughter, then advertise them as something new.