This is a Wild Area event held by Sword and Shield. This event hosts Ghost Pokemon, with a chance of encountering a Gigantamax Gengar and a Shiny Chandelure in 5-star raids.
This event created a precedent, as only "normal_encount", "normal_encount_rigel2" and "normal_encount_rigel3" files were actually updated to Index 81, whereas "dai_encount", "bonus_rewards" and "drop_rewards" remained unchanged from the old Index 80.
To import these files into your save, use PKHeX's block importing function. Our tutorial should guide you through it.
Our first post of this page contains some data relevant to the importing stage.
There's info and some common questions regarding Wild Area Events here.
To see other Wild Area Events, here.