From the Super Mario Wiki
Needlenoses are a type of Pokey that certain enemies spit. They take the shape of a yellow or green spiky ball. They can be turned into eggs. Needlenoses appear in Super Mario World 2: Yoshi's Island, Yoshi's Island: Super Mario Advance 3, Yoshi Touch & Go, Yoshi's Island DS and Yoshi's New Island.
Yellow Needlenoses, when spat at a Yoshi, will pop. Green Needlenoses will bounce. They can be spat from Priscilla the Peckish, a Blow Hard and its relatives, or a Wild Ptooie Piranha. A Needlenose will also sometimes bounce on top of a Cactus. If Yoshi defeats or eats the Needlenose, the Cactus will frown and lay down. However, it will reproduce another Needlenose shortly after. Needlenoses have a sub-species called Cactus Jacks. Also, they can be spit out by some Egg-Plants if Yoshi has less than six eggs with him.
Needlenoses will reappear in Yoshi's Woolly World, however they act differently this time. When they hit the ground they start rolling instead of getting destroyed.
- In a Nintendo Power issue featuring information about Yoshi's Island DS, they are called Pokeys. In Japan, they are considered a type of Pokey, although this was lost in translation.
- ^ https://www.youtube.com/watch?v=6FiCXHxcvdo