Bat-milk

Bat-milk is regular milk with a bat-prefix added by Batman.

Season one
With the Batmobile stolen, the gang offered the use of their Mystery Machine to Batman and Robin to search for their own vehicle back at the Batcave. As Shaggy Rogers got in the van, he asked Batman if he could have a snack while there. Batman was happy to oblige and said they'd all have bat-cookies and bat-milk, the latter of which worried Shaggy.

While at the Batcave, Scooby-Doo and Shaggy had their cookies and milk (where the latter found the cookie more questionable than the milk), although Scooby took Shaggy's milk while he was still holding his glass.

Appearances

 * The New Scooby-Doo Movies
 * 102. The Dynamic Scooby-Doo Affair

Notes/trivia

 * Contrary to what Batman said, nobody but Scooby and Shaggy had the cookies and milk.