are owl creatures found in the Tree Zone
of Super Mario Land 2: 6 Golden Coins
. They can be used as platforms to reach high places. When Mario
approaches one, he will wake up, and then and only then can he use one as a ride. The top of the owl's head is flat, making him an ideal platform for Mario to stand on while being flown to a higher area.
 Names in Other Languages
|From 「ぐうぐう」gūgū, an onomatopoeia for a snoring sound
- Heavy Zed, the Owls from Wario Land II and 3, and Hoot the Owl from Super Mario 64 are all very similar in that each one of them is a sleeping owl that flies the player to otherwise unreachable places when awoken.
- Their name comes from the common image in cartoons and games of someone sleeping with a trail of Zs next to them, and "heavy sleeper", meaning one who sleeps soundly and is hard to wake up. Also, since they are large enough for Mario to stand on, the "heavy" part of their name could be a reference to their weight.