Sound The Alarm!
The mummy in Only Halloween Town on Backyard Gang. He or She is fully wrapped in white cloth the only visible body part is one eyeball. He/she is friends with the corpse kid.
It is possible that he/she is a cyclops mummy, due to there being only one eye.
When looking for Jack, a vampire says he looked behind the cyclops eye, which might referring to this mummy.
In the picture to the side, it shows the mummy setting off the alarm. The reason he is doing this is because the Mayor tells him to because Jack Skellington has gone missing.