“Medusa” (0 out of four) was a toxically inept mess about a young woman (Megan Purvis) who is bitten by a snake and a deadly virus soon plagues her body and turns her life upside down. Grade-Z filmmaking is almost a throwback to something Ed Wood would have made back in his day. Story sounds like it might have some scares and bite but slipshod production and direction makes this all-but-unwatchable. Avoid like the coronavirus.