I know! My parent's were very lazy on the whole making me believe in mythical creatures part of my childhood (the Easter bunny never even removed price tags lol) but if they had, I cannot imagine all the therapy I would need..
My parents used talcum powder as santa's snow but that was a little after I stopped believing but it was fun trying to make my cousins still believe. But they used to ask why isn't it cold? and we would just say its magic snow...
For leprechauns on St. Patrick's Day (we descend from Irish so we get presents on the day), my mom used to bring in snow before me and my sister woke up and sprinkle it in the kitchen saying the leprechauns left footprints.
When I was eight I lost a tooth and put it under my pillow. I woke up during the night. My dad came in the room and said "go to sleep" and switched the tooth for the money. I'm like wow, great parenting.
I didn't stop believing in that stuff for a majority of my childhood because my mother was so committed. Honestly I probably believed for a little too long but I think that's what gave me my sense of wonder.
I'm going to do this... Except i'll use a different color.. This does look kind of shady