Fred's line "Who goes there?" is the title of the John W. Campbell Jr. 1938 short story which was the inspiration for The Thing from Another World (1951)/The Thing (1982)/The Thing (2011) which also takes place in Antarctica and features a humanoid monster. (However, the first adaptation changed the setting to the Arctic Circle.)
The title "Uncle Scooby and Antarctica" is a pun, meant to sound like "Uncle Scooby and Aunt Arctica".
"Uncle Scooby" was what Scooby-Doo was called by Scrappy-Doo, the diminutive canine who was his regular costar 1979-1988.