Amnesia-inator

The Amnesia-inator is a device from Dr Doofenshmirtz . It was used in Phineas and Ferb: Across the 2nd Dimension to make everyone forget the day and in Phineas and Ferb's Quantum Boogaloo as a complicated misfire that made Phineas and Ferb forget that Isabella had popped around and given them the tool, causing them to go to the future to get it.

Appearances
Phineas and Ferb: Across the 2nd Dimension

Phineas and Ferb's Quantum Boogaloo