Red ? Blocks are special type of ? Blocks that appear in Super Mario World and Paper Mario.
History
Super Mario World
Its first appearance was in Super Mario World, and there are only 2 in the game, found only in the Front Door/Back Door stages of the Valley of Bowser. This block is special and served only as activating/desactivating the spotlight in the dark room, which allowed to see in the dark. Unlike the traditional ? block, it doesn't turn into an Empty Block after being hit, as such the spotlight can be toggled on and off indefinitely.
Paper Mario

Red ? Blocks are found throughout the Mushroom Kingdom where one contains a Badge inside. Some Red ? Blocks are found in plain sight (such as the one on Goomba Road) while others are hidden that require a puzzle to be solved first to reveal it.