Fasnacht Day

Fasnacht Day, otherwise known as Fasnacht Parade, is a public event introduced in the Fallout 76 Wild Appalachia update. The quest was first available from March 19–26, 2019. It returned from May 27, 2020 to June 9, 2020. The quest returned for a third time as a Halloween event, every hour on the hour from 12:00 p.m. ET October 29, 2020 to 12:00 p.m. ET November 2, 2020.

Detailed walkthrough
To start the event, speak to the Master of Ceremonies in Helvetia at the top of the real-life hour (at XX:00). There's about a 9-10 minute grace period to speak to him before the event is automatically failed if not spoken to beforehand. Once started, the vault dwellers involved in the event must find five of the randomly-assigned Protectron marchers in the town. Each Protectron will provide a task corresponding to their profession, and each task must be completed before the parade can begin. After a task is finished, the relevant marcher will walk to the center of town, equip its Fasnacht mask, and wait for the others to arrive. The possible Protectrons and corresponding tasks are as follows:
 * Cheerful Beekeeper: Exterminate the honey beasts which are attacking the Honey Haus. There are usually three in all that need to be dealt with.
 * Happy Candlemaker: Donate beeswax from the Honey Haus hives to the Candlemaker (0/10)
 * Gleeful Butcher: Donate intestines from animals at the Butcher's Cooler (0/12)
 * Jolly Baker: Donate radtoad eggs from the stream to the Pantry (0/20)
 * Convivial Historian: Bring old Fasnacht steins to the museum for analysis (0/10)
 * Joyous Musician: Play some music onstage until the bar is full.
 * Jubilant Decorator: Decorate the barn (0/4)
 * Merry Woodsman: Add wood to the bonfire (0/50)

Once all five tasks are completed and all five Protectrons assemble in the center of town, the Master of Ceremonies rushes over to join them and take point as parade leader, and the parade begins its route. First, the group walks east down Pickens Rd. to the front of Freyja's Haus, the yellow-painted restaurant, where it is attacked by swarms of radtoads. The Protectrons can sometimes handle these on their own, depending on which ones spawned for the event. After the creatures are eliminated, the group moves north over the wooden bridge toward the Cheese Haus. The marchers stop in the middle of the field as super mutants, mutant hounds, and super mutant suiciders charge the group, with the suiciders being the biggest threat to the Protectrons if they get close enough to damage them when they detonate. Once the mutant assault has stopped, the marchers continue south. Finally, when the parade stops in front of the chapel, hordes of stingwings and wolves attack. A legendary megasloth also spawns near the post office. The enemies spawn and attack when the music played by the Master of Ceremonies abruptly slows and stops before recovering, then repeats once the attack is over and the parade resumes.

After the enemies have been killed, the Fasnacht bonfire must be lit. At least one Protectron marcher needs to be kept alive in order to complete the event, with more survivors netting greater rewards, otherwise, if all five are slain, the quest fails. The participants may also be granted a random legendary weapon or armor piece.

Masks
These are the available Fasnacht masks and hats:

Behind the scenes

 * Fastnacht is an actual annual carnival celebrated by Swiss and German people while traditionally wearing masks that represent demons, jesters, witches and animals. In Helvetia, West Virginia it is normally celebrated once per year on the first weekend after Fat Tuesday, and concludes with the burning of an effigy in a bonfire, without any robots or megasloths.
 * The music played during the Fasnacht parade is the 2004 One More Pils instrumental exercise composed by Andy Vale and licensed from APM Music. While the original piece is 1:10 minutes long, the version used in-game is comprised of two 15 second clips that endlessly repeat one after another.