Complex sentence: Doofus discovers the crystal, which he refers to as a "diamond doughnut", and presents it to Launchpad, but Launchpad can't identify what it is, and is unable to reward him with a merit badge.
Split into simpler sentences: Doofus discovers the crystal, which he refers to as a "diamond doughnut", and presents it to Launchpad. But Launchpad can't identify what it is, and is unable to reward him with a merit badge.