Two monsters went to a Halloween party...
Two monsters went to a Halloween party. Suddenly one said to the other, "A lady just rolled her eyes at me. What should I do?" The other monster replied, "Be a gentleman and roll them back to her."
This joke depends on the listener understanding the phrase "rolled her eyes" to mean "expressed disapproval to me by causing her eyes to rotate upward in her eye-sockets such that the pupil was not visible for a brief moment", not "caused her eyes to roll along the floor". The next sentence makes the listener realize that the literal interpretation is the correct one here. Since this is a monster joke, the thought of eyeballs rolling around on the floor is not that gruesome.
For someone who didn't have English as a first language, this would be a hard joke to understand.