Vampire Orientation consists of several trials for fledgling vampires to complete in order to come into their newly found powers.
Trial 1: Invisibility
The first trial is to use their new powers and become invisible. Marceline tells Finn and Jake that the best way to do so is to spin in circles and chant "invisible." She does this to humiliate the two, which leads to further pranking when the two attempt to frighten Lumpy Space Princess.
Trial 2: Toughness test
This segment of the orientation is merely an excuse to beat up Finn and Jake. Note that this segment of the test is made up by Marceline's friends, and she intervenes to prevent further harm to them.
Trial 3: Spooky vampire walk
Marceline hastily makes this segment up because she does not want Finn and Jake to hurt themselves by trying to fly. She uses the excuse that flying is too advanced a technique. However, Finn and Jake refuse to train for this.
Trial 4: Flight
Wendy, Booboo, and Georgy convince Marceline they have a plan for faking the flight, so they go to the top of a nearby tower, where Finn and Jake are pushed off. The ghosts reveal their plan is to let them die, so Marceline fast-falls to save them (while invisible), allowing Finn and Jake to complete Orientation intact and believe they are vampires.