When my kids were little, we did the whole Santa Claus thing for a few years.
As soon as they were old enough to ask me if Santa was real, mature enough to really question it, then I would tell them the truth.
After that, we stilled played Santa games around the holidays, but we added the Krampus into the mix. Krampus is the evil opposite of Santa, and we put up decorations for him too! That was a long time ago, my kids are in college now, but they still come home for Christmas, so I’ve added a new wrinkle. I call him Krannibus, he is the Christmas spirit of marijuana. My kids don’t know that I know, but I am fully aware that both of them smoke marijuana regularly. They think they are being subtle, not realizing that they reek of cannabis smoke every time they come to visit me. So this year after they went to sleep on Christmas Eve I slipped a few nice high quality marijuana nuggets into each of their stockings on the mantle. The next morning they opened up a few gifts, and then got into their stockings, and you should have seen their faces when they found a marijuana stash inside! They looked at each other in a panic, thinking it was from the other, then I explained the new legend of Krannibus, and how he leaves marijuana buds for good boys and girls. They had a big laugh at that, and then we spent the rest of Christmas day cooking food and smoking copious amounts of marijuana.