What is the difference between a mealworm and a caterpillar?

Oh, dude, like, a mealworm is like the larval form of a darkling beetle, while a caterpillar is the larval form of a butterfly or moth. So, you know, one turns into a cool beetle, and the other into a majestic butterfly. But hey, they both crawl around and eat stuff, so, like, they're basically distant cousins in the bug world.