It is a Krabby Patty with triple the amount of ingredients. Squidward orders one on a kelp bun with extra sea pickles and demands SpongeBob to "burn it to a crisp."
Role in episode
After Squidward eats a rather disorted and sandy Krabby Patty retrieved from its burial and realizes that he actually likes them, he wants another one, so he orders a Triple Krabby Supreme, but since he doesn't want SpongeBob noticing that he likes Krabby Patties, so he lets the customer's identity remain unknown. Squidward gets overwhelmed by watching SpongeBob cook the burger, so much so that he imagines a steam cloud from the grill, kissing his nose.
After SpongeBob finishes cooking it, he bursts out of the kitchen and exclaims the patty's name, asking who ordered it. Receiving no response, he comes to conclusion that the customer left, but Squidward recommends saving it in case they return. SpongeBob disagrees and states that a patty as special as the Triple Krabby Supreme should be eaten fresh, and since he hadn't eaten one in over 20 minutes, he does so and deems whomever ordered it to have great taste, then returning to the kitchen, leaving Squidward sad over the patty's disappearance.