Wario Land 3: Part 87: The Warped Void (Blue Chest)

At 0:55, jog toward the doorway, squeeze through the other side, jump over the gap to the left, and reach the shaft opened by the Blue and Red Key Cards. Drop a small enemy to defeat Enemy Blocks to the left, unlocking a doorway that leads into the blue section. In this area, the Blue Key and Blue Chest are in the same room but separated by walls and a doorway. First use Fat Wario to clear a Doughnut Block, then pass through its opening as Flat Wario from the other side to reach the Blue Key, and then navigate a different route to the Blue Chest. The Warped Void's Blue Chest contains a Heart Crest, a treasure to keep until you decide to share it with someone special.