McDonald's "Boo Buckets" will return on Tuesday, Oct. 21.

Spooky Season isn't Spooky Season without McDonald's Boo Buckets.

The Halloween-themed Happy Meals, a storied tradition since 1986, return to participating McDonald's restaurants nationwide on Tuesday, Oct. 21.

The decorative pails, which replace the classic Happy Meal box, have returned periodically in the years since their launch.

"Halloween buckets are popping up everywhere like ghosts in the night– and hey, imitation is the most BOO-tiful form of flattery," McDonald's said in a statement. "But let’s be real: there's only one OG Halloween bucket, and it comes with a Happy Meal."

This year's Boo Buckets, available while supplies last, feature five characters in total, three classic and two new additions, according to McDonald's.

From what's in them to when they'll be made available for purchase, here's what to know about McDonald's Boo Buckets.

What's in a McDonald's Boo Bucket?

McDonald's Boo Buckets, a customer favorite, come with all of the traditional Happy Meals fixings and may be used for trick-or-treating.

This year's pails, which feature familiar faces in Ghost, Pumpkin and Goblin, along with newbies Cat and Zombie, come in an assortment of colors, including white, orange, green, black and red.

Since each character has three different expressions, McDonald's customers will be able to collect all of the variations.

Boo Buckets also come with stickers, "giving folks the chance to customize their bucket to make them look fa-boo-lous," the restaurant chain said.

When are McDonald's Boo Buckets releasing?

McDonald's "Boo Buckets" will be available for purchase starting Tuesday, Oct. 21.

Contributing: USA TODAY's Max Hauptman, Mike Snider

This article originally appeared on USA TODAY: When are Boo Buckets coming back? What to know about the McDonald's Happy Meals

Reporting by Amaris Encinas, USA TODAY / USA TODAY

USA TODAY Network via Reuters Connect