Hoohoo is an owl-looking robot that appeared on Mega Man 9.
Those enemies are aerial and hold a rock that they throw before the player. The rock they throw can be either of earth or of ice, and if it touches terrain, it can leave debris. The debris harms the player character upon contact. Both the rock and the debris can be destroyed by the player's weapons, and can leave pickups.
When flying, they will fly at a set direction and stick to it, and they will go up and down in the shape of a wave. In the Level Builder, its direction can be set. There is also an invisible Spawner, which will make them appear undefinedly if the player is on the spawner's area.