From the Super Mario Wiki
Ice watermelons, also referred to as blue watermelons, are cold and frozen blue watermelons found in Super Mario World 2: Yoshi's Island, its remake Yoshi's Island: Super Mario Advance 3 and its sequel Yoshi's New Island. If Yoshi eats it, he will be able to breathe three blasts of ice in the original game and five in Yoshi's New Island. The ice can freeze enemies solid, which can then be smashed to pieces. In Yoshi's Woolly World, enemies that are frozen will slide along the ground when touched by Yoshi.
The Super Blue Watermelon Special Item is available in Super Mario World 2: Yoshi's Island and Yoshi's Island: Super Mario Advance 3, and the All-you-can-eat ice watermelon! Power Badge is available in Yoshi's Woolly World. Using them automatically places an ice watermelon in the air suspended by a propeller, allowing Yoshi to have its ability at nearly any point, as new ice watermelons will appear following him. In Yoshi's Island, using a Super Blue Watermelon allows Yoshi to spit ice nine times instead of the usual three.
Yoshi's Island: Super Mario Advance 3
Names in other languages
Super Blue Watermelon