It is a purple license card with bold letters at the top that read "Milkshake License." Below this, there is a text that reads "Class D" and three check boxes labeled "Chocolate," "Vanilla," and "Strawberry." At the bottom, SpongeBob's name is signed in cursive writing.
SpongeBob's photo on the license shows him holding his spatula.
Role in series
"Yours, Mine and Mine"
SpongeBob uses his milkshake license as ID to enter Patrick's rock. Patrick deems it fake, thus denying him access.
"License to Milkshake"
SpongeBob discovers that his milkshake license had expired seven years ago and goes back to the Milkshake Academy to get a new one.
Role in How SpongeBob Are You?
A picture of his milkshake license appears as one of the selectable choices on question 3.