Guavaween: With entertainment by pop rockers Tonic and Eve 6, the annual night of costumed revelry returns with motorized floats this year, so count on adding more beads at the Mama Guava Stumble parade. Make yourself visible if you want to get tapped for the costume contests. Gates open at 3 p.m. and the parade starts at 8 p.m. on E Seventh Avenue and N 14th Street in Ybor City. Tickets are $17 at the gate.
Florida Orchestra: Playing Mahler's emotional Symphony No. 7 at 8 p.m. at the Mahaffey Theater, 400 First St. S, St. Petersburg. $15-$45.
Thrill St. Pete: Hundreds of zombie faced dancers will gather for a flash mob of Michael Jackson's iconic dance number for Thriller. This is part of the simultaneous global dance Thrill the World stating at 10 p.m. at The Pier, 800 Second Ave. NE, St. Petersburg. Free.
Circus McGurkis: The peace festival and people's fair sponsored by the Religious Society of Friends (Quakers) returns with art, musicians, storytellers and more from 9 a.m. to 4 p.m. at Lake Vista Park, 1401 62nd Ave. S, St. Petersburg. Free.
John's Pass Seafood Festival: Kids should come in costume for a contest and trick-or-treating at 3 p.m. For the rest of us, there's lots of fresh local seafood, live music, a street dance and fiddler crab races from 9 a.m. to 6 p.m. at John's Pass Village in Madeira Beach. Free admission.
KIDS AND FAMILY
Wild n' Wicked Nights: The Weeki Wachee Mermaids put on a freak show and there's also costume and scream contests, hay rides, haunted mazes and more starting at 7 p.m. at Weeki Wachee Springs State Park. $5 for adults, $3 for 6-12.
From the Sky Down, 8 p.m., Showtime A documentary about how U2 almost broke up in 1991 after The Joshua Tree, but instead made Achtung Baby and became ridiculously famous.
SEASON PREMIERE Celebrity Ghost Stories, 9 p.m., Bio The most popular series in the network's history returns with Alan Thicke encountering a murderous Russian ghost in Moscow.
MORE TO EXPLORE
Find a monster list of Halloween events at tampabay.com/things-to-do.