The Cutie Mark Crusaders are stunned by seeing the baby Destroyahs, which are all inexplicably wearing diapers. Sweetie Belle curiously approaches one, but the baby belches Micro-Oxygen and her friends have to pull her away before she is killed. Then all the curious babies start doing it and the Crusaders take shelter in a trench, as the resulting blasts of Micro-Oxygen start wiping out the surroundings like mortar fire. They ask themselves what is going on when one of the babies follows them into the trench, happily playing with an apple.
They freeze up in terror, but another baby jumps into the trench and lands on the first one. In a flash of purple light and white mist, they fuse into one, becoming a toddler version of Destroyah. They struggle not to squeal at how cute she looks as she says that she is the original Destroyah. She speaks like a toddler but she still has her mind. She explains that she tried to trigger her ability to turn into a swarm of smaller versions of herself, but as a pony, she is unable to communicate with or control her duplicates. Now she has to recombine with them the old-fashioned way. They stick their heads out of the trench, only to find the babies are all gone.
The Flim-Flam brothers drive down the road on the way to Canterlot in their Apple Peelcore 8000, ready to collect their insurance money. They gloat about how they are really committing Insurance Fraud and nopony will ever know. A few days ago in Canterlot, their Super Speedy Cider Squeezy 7000 broke down, but all they had to do was claim Godzilla stepped on it during the battle against the Gyaos flock and they will soon be rolling in money.
A baby Destroyah jumps on their windshield. Curious, they ask where she came from and how she did that, but more of the babies jump in their vehicle and start trying to eat their crates of apples. The brothers try to control the vehicle and take their crates back, but are forced to bail out when the babies start belching Micro-Oxygen. The babies laugh until the vehicle crashes into town hall.
It is closing time for Ki Seong's restaurant and she ushers Cloudchaser out. She starts to clean up but leaves the door unlocked, believing "Quill Coat", whom she admits to herself she likes, will be coming in any second. A baby Destroyah enters the kitchen and knocks a pan over. Seong picks her up with her telekinesis and asks who would be stupid enough to leave their baby behind. The baby is holding a pepper container and breaks it open, sneezing Micro-Oxygen. Seong draws back as more babies appear and start wrecking the restaurant, but her face hardens and she stomps in preparation. No more Miss Nice-Kirin.
Rarity and Anguirus continue to stare at the baby Destroyah near the crashed vehicle until the real Destroyah tackles it and absorbs it, becoming a three-year-old version of herself. When she notices she's still wearing a diaper, she angrily rips it off. She and the Cutie Mark Crusaders explain what happened. Anguirus decides to take this opportunity to mock one of his most hated enemies since she is too weak to hurt him, but she angrily points out if her baby doppelgangers are allowed to feed, they will grow and mature. If they thought one of her was bad, they won't be able to handle an army. Rarity gets an idea after hearing how the babies think and behave like actual babies. She tells Anguirus to take the Crusaders inside while she makes a quick run to the store.
Rainbow Dash is napping on a cloud when she hears a scream. She finds the trio of Daisy Wishes, Roseluck, and Lily Valley running from their flower stand. She flies down, hoping it to be a monster to fight, but finds a baby Destroyah eating the flowers. She picks it up wondering what is going on when she notices the surroundings are covered with holes. The baby belches and Rainbow barely dodges it, losing part of her mane in the process. She sees more of the babies appear and prepares to escape when Rarity appears and levitates pacifiers into their mouths, calming them all down. The real Destroyah then absorbs them, turning into a filly just slightly younger than the Crusaders.
After explaining the situation to Rainbow, they hear a scream coming from town. Rainbow and Rarity realize it is coming from Sugarcube Corner and rush there as well as Anguirus. Destroyah cannot keep up with them because of their longer strides, but she notices more of the babies outside of town. The Cutie Mark Crusaders disobeyed Rarity's orders and followed them, but they arrive to see Destroyah rushing out of town.
Just as a baby knocks down Snips and steals his skateboard, Destroyah knocks down Snails and steals his bike. She rides towards the babies and then leaps towards them, but misses. Scootaloo arrives, towing the wagon with Apple Bloom and Sweetie Belle on it by riding her scooter. They scoop Destroyah into the wagon and Scootaloo gives chase. Destroyah sticks her body out of the wagon, forcing Sweetie Belle to hold onto her to stop her from falling out. With the weight imbalance and the extreme speeds they are going, they all have to work to keep the wagon from flipping over. Destroyah manages to grab and absorb one of the babies, but her sudden increase in size and weight jostles the wagon and Sweetie Belle flies out until Destroyah catches her. They nearly hit Tom the Boulder but manage to dodge it. Then they find four of the babies riding the discarded bike. One of them gets the hiccups and bombards the area with Micro-Oxygen blasts, forcing the four to dodge the blasts and flying debris. Apple Bloom manages to grab a fallen branch and pass it to Destroyah, who uses it to jam the wheels of the bike. Everypony gets flipped into the air and lands in a pond. The Crusaders surface and find Destroyah absorbed the four babies, and has become the same age as them. She gives a warm smile and says that was awesome, then gets embarrassed and says they have no time to waste before moving back into town. The Crusaders are left stunned. She looks so different when she's genuinely happy.
Rainbow Dash enters Sugarcube Corner and finds Pinkie Pie trying to make the babies go away by throwing food at them. Rainbow explains how feeding them will only make it worse. They start rounding them up when Discord teleports in. He just sensed that something chaotic was going on and wanted to see what was causing it. One of the babies suddenly belches and the Micro-Oxygen vaporizes his head. Before Rainbow and Pinkie can scream, the immortal reality warper simply conjures up a new head. Rainbow and Pinkie ask for help before the babies eat up all the food. Discord gets confused and comments that he thought Destroyah can eat anything. To their confusion, Discord uses his ability to break the fourth wall and conjures up a Kindle-Fire that connects to the real world's Internet. He looks up Tohokingdom and the TV Tropes website itself and reads how Destroyah lost her immunity to her own Micro-Oxygen in pony form. Having no idea what he is doing, they beg him to make the babies stop eating all the food. He says fine and zaps the babies, explaining that he altered their metabolism. He then notes that he's almost late for his tea time with Fluttershy and teleports away. Unfortunately, the two discover Discord granted their request by giving the babies back their immunity to Micro-Oxygen. They leap out the back door as the babies start dissolving everything in the bakery and eating it.
Twilight Sparkle, Mothra, and Spike teleport into the library. Mothra had wanted to practice the teleportation spell, but the effort of casting it tired her and she finds it a little hard to maintain her Alicorn disguise. Since she's still a novice at Changeling shape-shifting, it is difficult for her to hide her horn and wings, so she decided to disguise herself as an Alicorn. It raises some suspicions because there are only supposed to be four Alicorns in Equestria right now: Celestia, Luna, Cadance, and Twilight, but Mothra figures it is better than being mistaken for an evil Changeling.
Rarity and Anguirus arrive and explain the situation. Outside, the babies are now eating everything in sight. Twilight is reminded of their earlier Parasprite infestation. Determined, Mothra steps outside and says she will handle this. They protest, but she forces them all inside with telekinesis and then seals the door shut with a spell. They are unable to break it down and even Twilight and Rarity combining their powers does nothing. Anguirus explains that while he doesn't know much about magic, he can tell Equestrian and Terran magic works off different sources and are incompatible. Twilight begs her to let them out, but Mothra says she can't take that risk, not against Destroyah. It will be fine, for she also has the ability to divide herself. She concentrates, but instead of turning into a swarm of hawk-sized moths, she turns into a swarm of Breezies. After getting over the initial confusion, the Breezies start rounding up the babies
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DJ-Pon3 or Vinyl Scratch starts up her radio show and gets a call from the spa ponies screaming about how they are being attacked by babies who are eating everything in sight. She thinks this is a prank call, but four of the babies enters the studio. She asks her roommate Octavia where they came from, but she is not there. Even when the babies start eating everything, she just nonchalantly continues her show.
Irys and Megalon watch over Gigan, who passed out after finishing his tale. Eventually, Irys decides she can't take it anymore and leaves demanding answers, ignoring Megalon's protests that they have to stick together. She finds Grand King Ghidorah, and despite every instinct warning her to stay away from him, demands to know what he knows about Monster X and Kaizer Ghidorah. Unimpressed, he boasts that she is as a cockroach before a god, and since their master isn't here, he doesn't have to tell her anything. He turns to walk away, but she attacks him. He easily knocks her back, but she takes out the torches, leaving the chamber in complete darkness. His body glows, but it is not nearly enough to pierce the darkness. Then he hears a strange pinging and realizes she can use echolocation. He grows in frustration as she attacks him again.
