It is a normal day in Bikini Bottom. A jellyfish drifts by. SpongeBob and Patrick skip after it, flailing their jellyfish nets.
Patrick springs to catch the jellyfish, but he misses and it stings him on the chest. To make matters worse, he lands on the edge of a cliff and tumbles right off, screaming the whole time he's falling. The jellyfish laughs mockingly—and suddenly finds itself captured.
Turns out SpongeBob (who was standing a few feet away) had extended his arm so that his net was directly over the jellyfish, and then scooped it up. He brings his net (with the jellyfish still inside) back towards him and does his signature laugh.
In the TARDIS, utter chaos. It keeps jerking back and forth, there's a low rumbling sound, the alarm sounds, and there's smoke everywhere.
"What's going on?" Leela screams in a half-frightened, half-frustrated tone.
"You know those ScorpionBots?" the Doctor asks. Leela nods worriedly, recalling those robotic scorpions that had invaded the citadel on Gallifrey. They would destroy everything in their path, and K9 eventually had to set his self-destruct to the highest possible setting to get rid of them all. She'll never forget their chilling words: Must get formula at all costs.
"I don't think they all died in the explosion," the Doctor says grimly. Just then, something chews its way out of the control panel. It's a ScorpionBot! "Must get formula—" it says, then grabs the Doctor's scarf and pulls hard before finishing the sentence: "at all costs."
He's so busy gagging and trying to fight it off that he doesn't notice a little robotic dog in the back of the console room. "Do you require assistance, master?" is barely audible over the alarm.
Suddenly, a laser beam shoots the ScorpionBot that's hanging on the Doctor's scarf and atomizes it. The Doctor regains his composure, loosens his scarf, searches for the source of the laser that had saved his life, and is both excited and surprised to see K9 back in one piece. Leela is just standing off to the side with her eyes and mouth wide open.
"How did—?" the Doctor starts to ask excitedly; but K9, sensing that there were a lot more ScorpionBots in the console, hurriedly says "No time to explain right now," and shoots at every robotic arthropod that comes out of the hole. They all chant "must get formula at all costs", but the ones in front don't even get the first letter out before K9 zaps them. There is the occasional ScorpionBot that clones itself, but even then they are no match for K9.
Suddenly, there's a big THUD! Leela is thrown on top of the Doctor, who is then knocked right off of his feet, and both of their heads hit the door. Miraculously, K9 (who is still battling the ScorpionBots) doesn't move an inch.
Patrick is still falling (bottom-first, and with his legs spread out) and screaming. Much to his surprise, he lands on the TARDIS. "OOMPH!" His head and body stop dead, but his limbs keep falling and form 2 holes in the ground—one in front of the TARDIS, and one behind.
The force from the Doctor's and Leela's heads is enough to knock the door wide open, and both the Doctor and his companion tumble out into the water. Patrick starts screaming again. Leela does a nosedive into one of the holes in the ground. Patrick's scream fades into a laugh.
Leela screams and throws a pink thing out of the hole. Patrick looks down and instantly stops laughing. She is getting ready to destroy it, but he jumps to the side and yells "Gimme that!" The Doctor picks up Patrick's right arm and reattaches it.
Leela then proceeds to throw the other limb—Patrick's right leg—out of the hole and climb out. Patrick grabs the leg and reattaches it—in the socket of his left arm! "I don't think that's right," the Doctor says. He pulls out his sonic screwdriver, tries to turn it on—and the top part explodes.