Suspecting someone was in the bushes, ready to ambush him, Norman sent Slaking to use Swagger. However, nothing happened, so Norman walked away, unaware Ruby had Kiki use Safeguard to protect themselves. Blaise had his Slugma create fires to make Ruby hallucinate his worst nightmares. Thus, Ruby saw an illusion of Norman and his Slaking.
At the Weather Research Institute, Norman sent Slaking. Ruby tried to flee on some stairs, which Slaking pulled away. Thus, Ruby sent Nana and Kiki to battle Norman's Slaking and Vigoroth in a Double Battle, where Slaking used Hyper Beam. After resisting Ruby's attacks, Norman had Slaking use Bulk Up. This made Slaking strong enough to pull the stairs and made Ruby hang onto them.
After walking away from the Gym Leaders' meeting in Fortree City, Norman faced a Shiftry. Thus, Slaking was sent out, who defeated Shiftry in one move. Ruby also remembered fighting Norman and Slaking after his Mumu evolved into a Swampert.
At the Sky Pillar, Slaking and Spinda were battling Wally's Flygon and Kecleon in a Double Battle. After getting hit by Astonish, Slaking's Truant ability was swapped with Spinda, who used Skill Swap. This allowed Slaking to freeze Kecleon and Flygon with Blizzard, while Spinda confused them with Teeter Dance.