From the Super Mario Wiki
Retrieved from "https://www.mariowiki.com/index.php?title=Blue_block&oldid=2440266"
A blue block is an object from Wario: Master of Disguise. They are a blue version of the red blocks which appear throughout the game and function similarly. However, unlike red blocks, Wario cannot destroy blue blocks with Dragon Wario's regular fire breath. Wario must obtain the Dragon Mastery Gem and turn his breath blue in order to destroy blue blocks.