Ring ~ The Polyjuice Potion

Ring ~ The Polyjuice Potion (リング　～　ポリジューズポーション) is the second episode of the second season of Magical Girl Team Lucky Star and the 60th overall. In the episode, Konata, along with Susumu Hori, Patricia Martin, and Tsukasa Hiiragi, take Polyjuice Potion for the first time in order to find out about the heir of Mizudan without being caught.

Plot
The episode begins with Konata showing three of the other Lucky Stars her new cell phone, and reveals her ringtone to be The Mikuru Legend of Love. After listening to it, Kagami tells Konata she wants to find out more about the heir of Mizudan. While searching through the Suzumiya bloodline on Ancestry, they find that almost the entire Suzumiya legacy is in Mizudan. While trying to figure out the true heir, they want to question Haruhi's father about this, but due to it being too dangerous to enter Haruhi's home, Tsukasa and Miyuki suggest using Polyjuice Potion to disguise themselves as members of SOS Brigade to avoid being detected.

While Konata is visiting the Hiiragi household, Tsukasa goes online and looks up information to make the potion, and thinking she wants to make it right now, Konata tells Tsukasa that she doesn't have the ingredients to make it. Tsukasa sends two of her elder sisters, being Inori and Matsuri, to the local supermarket to buy the ingredients. After returning back, Tsukasa begins brewing the potion. While the potion is being brewed, Konata asks Kagami to find and grab hair samples from their targets. Additionally, Konata texts Susumu to take part in this operation.

To avoid detection, the group, along with Susumu, sneak into Haruhi's school and go inside the girl's bathroom to partake the potion and complete the disguise. Because Kagami was unable to grab the hair samples from Haruhi and Mikuru, Susumu uses three apples containing sleeping draught to give Haruhi, Mikuru, and Kyon general anesthetics to make things easier. Using the Levitation Charm, Konata controls the apples directly to them. After Haruhi, Mikuru, and Kyon take a bite from the apples, they fall asleep almost instantly and grabs their hair samples from them.

Susumu, Konata, and Patricia return to the bathroom that Tsukasa was previously in. Tsukasa says she brewed a pretty decent potion and that the effects last an hour. After Tsukasa loads the potions and the others loading their hairs in, they drink the potion. Pretty much everyone who took the potion felt sick during the transformations. Konata transforms into Haruhi Suzumiya, Susumu Hori assumes Kyon, and Patricia Martin takes on the form of Mikuru Asahina. When the three try to get Tsukasa along, she ends up turning into a creeper due to the fact that Yuki's hair sample had gunpowder in it.

The three eventually go to avoid wasting time and encounter Haruhi's father. The three question him about the heir of Mizudan and learn that the mechanical basilisk owned by Team Ankoku hasn't been operated since The Invasion of '83. They learn that the last time it was used, a very important woman, being Kanata Izumi, had died from its power by Dr. Manhole. After a long discussion, the effects of the potion wear off and they run back to avoid being detected. When Konata tries to tell Tsukasa about the loads of things they learned, she tells her to go away, but Queen Kanata steps in and says the potion wasn't meant for animal transformations. They look inside and see Tsukasa as a creeper.