E is for Ectoplasm

Plot:

Andrew and Zelda break with their respective traditions and decide to throw a joint Halloween party, much to the dismay of Stu and Stephie, who feel like they are losing their best friends. Meanwhile, with Big Bird looking for a solid promotional opportunity to boost the profile of the company, Henry takes it upon himself to enlist the help of Ray Parker Jr. to attend their annual Wallflower Halloween party.