LOL! I love Chia Pet jokes. I'm thinking of getting my husband one as a joke.
My brother in law got one of these gag gifts for me one time, it was a spilled coffee inside a cup that looked like it come from a coffee vending machine. I thought "EW!" and was going to clean it up. I picked up the cup and I realized the gag when everything including the spilled coffee stain and straw came off the table as well.