A list of Endings in Adventure High.
There's currently one.
Mass Bimbofication
To get this ending, enslave Val at any point of the game. Get her to level 4 and talk to Ms. Rack. Ms. Rack will remark that Val is acting strange. Lie to her about this.
Next, level Val to 14 and have access to the Flirt spell.
Once done, speak to Ms. Rack again and use the Flirt spell at any point during the conversation. Choose either option when presented, then use Boost during the scene that follows.
After that, speak to her again. Val will transform Ms. Rack into a bimbo. Head back to the room, change Val back to her bimbo form, then speak to Ms. Rack again.
Once done, head to the first floor of the Dungeon and touch the Sigil.
During the scene that follows, everyone in the school (presuambly with the exception of the Protagonist) turns into bimbos.