At Easter, my family had a tradition where Easter Bunny left notes telling us where the next set of eggs were and we'd follow a trail of clues around the house. I thought everyone did it that way
My understanding is they usually just hide eggs around the house or yard and search, what was unusual was Easter Bunny giving us notes telling us where to look
Maybe your family started early with explaining data structures, and this was their introduction to linked lists. Did you also have some family holiday featuring a red/green tree?