Twirling with a Bang! (Japanese: 激突ウルトラビースト！ドンドンバチバチ大作戦！！Ultra Beast Clash! The Great Crackling Rumble Operation!!) is the 78th episode of the Sun & Moon series, and the 1,017th episode of the Pokémon anime. It first aired in Japan on June 7, 2018, in New Zealand on October 5, 2018, in Canada on October 27, 2018, in Australia and the United Kingdom on October 31, 2018, and in the United States on November 10, 2018.
Ash is back on Melemele Island, watching a fireworks display with his Pokémon School classmates. Toward the end of the show, a strange creature starts creating even more fireworks—by making its own head explode! The next day, Lusamine summons the Ultra Guardians to deal with this Ultra Beast!
When our heroes go after it, they discover a second Ultra Beast, and the two creatures face off, flinging fireworks and sparks around so no one can get close. At Ash’s suggestion, the Ultra Guardians stage their own fireworks show, combining their Pokémon’s moves into a gorgeous display that distracts the Ultra Beasts long enough to catch them!
At night, Ash and his friends watch fireworks, some in the shape of Pokémon, light up the dark sky. The display ends and the crowds quickly disperse, though Ash and his classmates notice a rogue firework go off. It suddenly retracts into a round white ball and begins bouncing around. Kiawe checks his information pamphlet which states that the fireworks show should be over, but the group and some of the crowd enjoy the encore. The white ball object returns to the body of a mysterious being, who happily performs on a rock out at sea. It rushes over to the group and explodes. The startled crowd continues to be amazed by the walking firework's theatrics. A few more explosions cause an Ultra Wormhole to open and a Xurkitree to land on Alola's shores while the crowd watch the being flee across the ocean.
The next day at the Pokémon School, the heroes wonder if yesterday's mysterious creature was an Ultra Beast. Komala rings the school bell furiously and Professor Kukui sends the students to the Ultra Guardians base underneath the school. The group quickly morph into their costumes and reach the base where the activated monitor displays Wicke, Lusamine and Professor Burnet. Lusamine greets the Ultra Guardians, and after analysing footage from last night's fireworks festival she has deduced that the mysterious creature is indeed an Ultra Beast. Rotom updates it data on Blacephalon, informing the Ultra Guardians that it explodes its head and absorbs people’s reactions to energise itself. The lights suddenly go out, putting Sophocles into a panic. His Togedemaru provides some light with her sparks to calm him down. Lusamine's Clefable switches on the back-up power and Lusamine announces that they have such detected the Ultra Aura on Melemele Island’s Route 3 by some power lines. The Ultra Guardians are dispatched on their Ride Pokémon to the scene.
The group soon arrive, but are surprised to see a different Pokémon, Xurkitree instead of a Blacephalon. Given that they arrived at the right scene, they believe it is an Ultra Beast as well. Xurkitree rears itself from the power lines and goes on the attack. It sends a bolt of electricity towards the Ultra Guardians, but they manage to avoid, before continuing to feed on the power lines. Lusamine calls through and confirms the group's suspicions, and Wicke stops the electricity flow to the area. As Lillie predicted the Ultra Beast was feeding off the electricity, Xurkitree begins to spasm as its source is stopped. While Ash and Sophocles send out their Electric Pokémon to confront Xurkitree, the other Ultra Guardians have their Beast Balls on standby. Ash tells Pikachu to use Thunderbolt, and Sophocles has his Charjabug and Togedemaru use Discharge and Zing Zap respectively. The large bolts of electricity instantly draw Xurkitree's attention and it leaps off the electricity tower and a pursuit ensues. Just as Kiawe, Lillie, Lana and Mallow are about to throw their Beast Balls, Blacephalon arrives unexpectedly and explodes.
Blacephalon's attention soon turns to Xurkitree, and the two engage in a show of light. With the pair distracted, Kiawe calls for everyone to have their Beast Balls at the ready. When they throw them, the balls get caught up in the light display and miss their targets. The wired-like Ultra Beast emits electrical whirlpool which fuses with Blacephalon's blasts to create an incredible galaxy-looking display. Lusamine calls through again, she informs the group that the wired-like creature is an Ultra Beast called Xurkitree, an Electric-type Pokémon that creates shockwaves. She like Lillie is deeply concerned, and states that the two Ultra Beasts are rivals who will likely continue to compete in an escalating performance battle that threatens the Alola region. Ash suddenly comes up with an idea: to use the group's Pokémon to launch a firework of their own. Everyone is in agreement, so Ash sends out Lycanroc, Kiawe calls on his Turtonator, Lana's Popplio, Snowy, Mallow's Steenee and Charjabug all lend a hand.
Togedemaru and Charjabug use Zing Zap and Discharge, to fuse with Pikachu's Electroweb. Popplio follows with a Bubble Beam, Steenee fires Magical Leaf. Charizard and Turtonator's Flamethrower, and the Poké Ride Garchomp, Altaria and Flygon send out a Fire Blast. Xurkitree and Blacephalon stop to watch the performance as Snowy adds a Powder Snow to the swirling display. Poipole chimes in with its own attack, and surrounds the fireball with red sparkles. With the two Ultra Beasts distracted, Ash calls on Lycanroc and it unleashes its exclusive Z-Move, Splintered Stormshards. As the dust clears, the pair of Ultra Beasts are shown to be stumbling around and weakened by the attack. Lana throws her Beast Ball while Lillie follows suit, and with a helpful sepal whip from Steenee, the Ultra Beasts are caught. Lusamine, Wicke and Burnet marvel at the Ultra Guardians' growth and are relieved to have the situation resolved.
The next day they join the Ultra Guardians, and Tapu Koko watches from overhead, as Xurkitree and Blacephalon return to their respective worlds. The students later return to school where Kukui announces that their duty is not over yet. Since the Ultra Guardians success, several event venues have requested that the heroes to repeat their firework performance. Everyone wonders if they can repeat the spur of the moment display. Unbelievably, Lana looks at the request as a lucrative business opportunity.