Simple Easter Egg if all you are looking for is a single perk. If you want all perks, there is another guide up for that.

For this, you need to find 3 PHD flopper bottles.
Bottle 1: On top of the wundersphere at spawn
Bottle 2: On a shelf across from the well in the power station. It's the shelf next to the teddy bear.
Bottle 3: On top of a basketball hoop in the main courtyard. It's the one behind the box location near the wundersphere.
When all 3 are shot, a perk bottle will appear in the teleporter.