Waddle Doos are a recurring enemy in the Kirby series. When Kirby inhales them, he is given the Beam ability.
They also appear in I Wanna Be the Boshy as obstacles in World 2.
How hazardous are they?Edit
Well, that depends on where they are. Usually, they're a big threat. They will often shoot a large laser, similar to that of Hello Kitty. One Waddle Doo, when shot, will release much more Waddle Doos. Another Waddle Doo ends up breaking the entrance to King Dedede's tryouts with its laser, then passes out.
Waddle Doos also appear in the fight against Kracko. Kracko will shoot several of them as one of the attacks in the pattern.