It's a mix of every other Special Seed. The Drunk Seed, Not the Bees, For the Worthy, CelebrationMk10, The Constant, No Traps, and Don't Dig Up. To make things even more chaotic, the Mech Bosses are a little different.
Without Spoiling everything, here's a list of changes you should know about.
The world has both Evils, The Dungeon is under a Living Tree, There's a ton of honey in the Underground layer (Not Cavern, the small layer right under the True Surface.) Queen Bee Larva are common, Living Mushroom Biomes are painted and the one above Hell has Crisp Honey instead of Stone, Crisp Honey burns you and causes Lava when Mined, (Like Hellstone) you have The Constant's Hunger, the world difficulty's is increased to one setting higher than usual, (Even on Master Mode. That upgrades to Legendary Mode.) For The Worth upgraded the Bosses, and you explode into Confetti if you die. Hope you like Confetti!
Also, No Traps does something with the number of Traps. I forgot what though.