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DP043 : Malice In Wonderland!
Pokémon the Series: Diamond and Pearl
DP045 : Ill-Will Hunting!
Mass Hip-Po-Sis!
DP044   EP510
Save the Lost Hippopotas!
First broadcast
Japan August 23, 2007
United States January 5, 2008
English themes
Opening Diamond and Pearl
Japanese themes
Opening Together
Ending 君のそばで 〜ヒカリのテーマ〜(PopUp.Version)
Animation Team Iguchi
Screenplay 大橋志吉 Yukiyoshi Ōhashi
Storyboard 山田浩之 Hiroyuki Yamada
Assistant director 山田浩之 Hiroyuki Yamada
Animation director 夏目久仁彦 Kunihiko Natsume
Additional credits

Mass Hip-Po-Sis! (Japanese: 迷子のヒポポタスを助けろ! Save the Lost Hippopotas!) is the 44th episode of Pokémon the Series: Diamond and Pearl, and the 510th episode of the Pokémon anime. It first aired in Japan on August 23, 2007 and in the United States on January 5, 2008.

Spoiler warning: this article may contain major plot or ending details.


Ash's Turtwig brings everyone's attention to a young Hippopotas that's stranded on the ledge of a cliff. Ash hauls the Hippopotas to safety, and it insists on following him. Then Rhonda and the Sinnoh Now news team arrive on the scene, and they want to follow Ash around, too! Rhonda wants to see Ash reunite the Hippopotas with its migrating herd. Team Rocket, of course, wants to steal Hippopotas, but between Hippopotas's Yawn attack and Ash, Team Rocket barely even manages to slow our heroes down.

Of course, Team Rocket won't quit that easily. They come back for another try, using a piece of fruit to lure Hippopotas into their balloon. But when Hippopotas uses Sand Tomb, their plans are sunk just as fast as their balloon, and Hippopotas happily returns to Ash. Next Ash has to cross a narrow bridge across a river, and when Team Rocket attacks, Hippopotas falls in the river! For a Ground-type like Hippopotas, that's bad news.

Hippopotas is rushed to the nearest Pokémon Center, where Nurse Joy has it feeling fine in no time. The quest for the Hippopotas herd resumes, and the gang encounters a strangely familiar group of sand salesmen. They turn out to be Team Rocket, of course, but the thieving trio didn't count on Hippopotas and that Yawn attack, which puts Jessie to sleep. Meowth and James' Cacnea are no match for Pikachu and Ash's Turtwig, and once they're gone, our heroes keep searching until they find the Hippopotas herd. The lost Hippopotas is back where it belongs and Ash is headed back on the road to Hearthome City—after a Yawn-induced nap, that is!


After a lunch break, Ash, Dawn and Brock recall their Pokémon and prepare to hit the road once again. Pikachu suddenly imitates Turtwig, and Brock realizes that Turtwig went by itself into the woods. Following its trail, they find Turtwig, who points them to a cliff where a frightened Hippopotas is trapped. Deciding to help it, Ash climbs down the cliff, with the help of a rope onto the ledge where Hippopotas is. Ash tries to reassure Hippopotas, but he is too frightened and bites Ash’s hand. Ash calls Pikachu who slides down the rope, and comforts Hippopotas, with success. Ash promptly hoists Hippopotas into his arms and they are lifted to safety by Brock and Dawn. Brock hands Hippopotas some Pokémon food, however it doesn’t like the taste. Instead, Hippopotas walks over to a nearby fruit tree, so Ash gets a fruit for him, which Hippopotas devours whole.

Ash and his friends prepare to leave, saying goodbye to Hippopotas, however the young Pokémon continues to follow them. Suddenly Rhonda and her staff from Sinnoh Now show up for a scoop about a herd of Hippopotas. Rhonda instantly recognizes the group and informs them that a male Hippopotas got lost from his family. After hearing the story about his family, Ash’s group decides to help Hippopotas return to his family.

They set off in searching for the herd with Hippopotas and the TV crew following them, but they all fall into a pitfall trap set up by Team Rocket who takes Hippopotas in their balloon. Being scared, he responds with a Yawn, which hits Meowth. Ash sends out his Turtwig which uses Razor Leaf to cut Hippopotas from his restraints. He falls and is caught by Ash releasing another Yawn which hits Brock and Jack. Jessie is left feeling frustrated as Ash and the others flee with the Hippopotas while Meowth drifts off to sleep. James convinces Jessie that they should go after Hippopotas for the boss, even providing his own boss fantasy.

Brock suddenly succumbs to the Yawn attack, collapsing on the ground. Ash and Dawn notice Team Rocket flying overhead and decide to hide behind a nearby bush. They quickly realize they forgot Brock, though Croagunk drags Brock behind the same bush. Meanwhile, Rhonda is annoyed as she is forced to hold the microphone boom while one of her staff carries the now sleeping Jack on his back. Later, Ash and his friends stop at a roadblock, where a bridge is under construction. While distracted, Team Rocket lures Hippopotas into their balloon with the help of a fishing rod and a bait. Hippopotas uses Sand Tomb to bring the balloon down to the ground. Ash sends out Aipom who uses Focus Punch to send Team Rocket blasting off. Back on Ash's head, Hippopotas releases another Yawn, this time on Dawn, making her drowsy, and eventually fall asleep.

Next, they continue their trek with Dawn being carried on Brock's back. They come across another bridge, which they proceed to cross. Team Rocket shows up and uses a net to capture Hippopotas. Ash jumps on the net which breaks and they both fall into the river below. Brock sends out Croagunk which uses Poison Sting to send Team Rocket blasting off again. Dawn turns her attention to Ash and Hippopotas, and sends her Buizel outs to rescue them. Once ashore, Dawn immediately dries Hippopotas because he is weak to water before taking him to the nearest Pokémon Center for treatment. After a check-up, Nurse Joy places Hippopotas in a box of sand to rest and dry himself. Ash and his friends retrieve some more desert sand which helps Hippopotas make a quick recovery and they set off in searching of the herd again.

On their way out, the group spot some roadside sand traders, none other than Team Rocket in disguise. Not recognizing the trio, Hippopotas releases another Yawn on Jessie and Ash decides to let Hippopotas try the sand, before buying it. Team Rocket closes the bag, trapping Hippopotas inside, before revealing their true identity and rushing to the balloon. As they recite the motto, Jessie starts to fall asleep, and Hippopotas escapes from the bag. Ash and his friends are furious, and respond back with own rip-off of the Team Rocket motto to intimidate James. James calls Cacnea out to battle and Ash sends out Turtwig. Cacnea unleashes a Pin Missile, but Turtwig dodges and uses Bite then Razor Leaf followed by a Tackle and Pikachu uses Thunderbolt and sends Team Rocket blasting off again for good as Jessie wakes up.

The group heads off to a large desert, where they spot recent Hippopotas footprints. Aside from the sand dunes, nothing is in sight. Hippopotas calls out to its friends, resulting in plenty of Hippopotas popping out of the sand. They leave Hippopotas there, but, before that, Ash tosses him a fruit, which he gobbles down in a single bite. Hippopotas replies by releasing another Yawn, which lulls Ash and Pikachu to sleep. Later, the group continue onwards to Hearthome City with a sleeping Ash being carried on Brock's back while Dawn holds Pikachu in her arms.

Major events

For a list of all major events in the anime, please see the history page.


Pokémon debuts






Dub edits

  • In the Polish dub, as Team Rocket blasts off, Meowth doesn't mention Cassidy at all.

In other languages

DP043 : Malice In Wonderland!
Pokémon the Series: Diamond and Pearl
DP045 : Ill-Will Hunting!
Project Anime logo.png This episode article is part of Project Anime, a Bulbapedia project that covers all aspects of the Pokémon anime.