BATH, Maine — The Pine Tree State has no shortage of unexplained crypto creature encounters. There’s Cassie the mythic Casco Bay sea monster, first reported in the 18th century. In the 1970s, kids say they saw a gorilla on the loose in Durham. Bigfoot was reportedly sighted in Turner just a few years ago. Now, thanks to three Morse High School students, we can now add another to the list: The Basin Screecher. Juniors Alden Harkin and Gavin Hanna, along with senior Owen Barter, produced an eight-minute, comic documentary film about the local Phippsburg legend.