618 - Little Green Men and a Fella's Marriage Proposal
Aired Thursday, April 27, 2023

Sheldon wants to search for life on other planets and Mandy answers Georgie's marriage proposal. Also, Missy is caught between two friends.
- Guest Stars:
- Emily Osment as Mandy
- Ed Begley, Jr. as Dr. Linkletter
- Wallace Shawn as Dr. John Sturgis
- Wendie Malick as President Hagemeyer
- Melissa Peterman as Brenda Sparks
- Wyatt McClure as Billy Sparks
- Wil Bowers as Dr. Thompson
- Jim Hanna as Dr. Hayes
- Penny L. Moore as Dr. Evans
- Dhruv Uday Singh as Dr. Prakash
- Stewart Skelton as Dr. Adams
- Writers (Story):
- Steven Molaro
- Jeremy Howe
- Marie Cheng
- Writers (Teleplay):
- Steve Holland
- Eric Kaplan
- Nadiya Chettiar
- Director:
- Matthew A. Cherry