This achievement is story relevant so it can't be missed.
*** Spoiler - click to reveal ***After Laverne got her tentacle costume with have her climb down the chimney.
At the bottom, talk to the blue tentacle right next to the chimney and sign up your human for the show.
Then go upstairs and in the second room find the mummy.
Get the roller skates from the table on the right and use them on the mummy.
Push the mummy out of the room.
Go downstairs, and attach the name plate you got from the blue tentacle to the mummy.