Waddle Doo's Bad Luck is a reoccuring running gag that Waddle Doo endures in the Kirby: Behind the Scenes series, first shown in the series' first installment. It is responsible for the many unfortunate things that happen to him. It will be revealed in Kirby: Behind the Scenes 3: Dark Matter Chronicles that Waddle Doo got his bad luck from a penny he found while he was picking up Dedede's drycleaning. He thought it was lucky but it later turned out to be unlucky instead.
Later on that afternoon, he tried to pick up Dedede's mallet to guess it's weight but it ended up smacking him on the head, making him into the dumbass he is now. After his death in Chapter 10, Waddle Doo switched his luck with Raven's. However, Raven only got minorly injured or bruised until Death noticed the switch and swapped the lucks back to the way they were.