It's The Pigs, Darling

Unlock Condition: Hit 3 pig balloons.

Chapter: 16

While floating backwards through areas, you'll eventually fly above buildings and enter a section with large pig-shaped balloons. Steer into 3 of them as you float. The trophy doesn't unlock until the end of the section when you float into Rockford's house and the scene switches back to Cassandra's Room.