The materials & set up for this Easter egg idea:

White eggs, hardboiled
A new set of 80s glam Sharpie markers
Cheap plastic placemats to protect the table (from Ikea)
Silicone ice cube molds (an impromptu idea for holding the eggs in place—you could also use egg cartons or muffin tins)
Individual cups to keep eggs from rolling around as the child draws
Kool-Aid + white vinegar for dyeing the eggs (or use food coloring or any commercial kit)
Tongs