Danny is the Gym Leader of the Navel Island Gym from the Orange Islands. Danny approached Ash, Misty and Tracey and complimented Misty, causing her to be flattered. He accompanied Ash when they climbed the mountain, then fought against Team Rocket for their attempt at stealing Pikachu. At the top, Misty and Tracey realized he was the Gym Leader.
After this revelation, Ash and Danny had three challenges. He used Nidoqueen against Ash's Lapras to freeze the geyser and won. The next challenge was to shape the ice like a sledge, which Ash won as his Charizard burned him, melting the parts of the ice. The last challenge was a race, but it was temporarily stopped due to Team Rocket's attempt. Ash and Danny continued the race and while the odds were in Danny's favor, Ash's slide spun around and he landed in the sea. But luckily, Ash managed to win the race and the badge.
Nidoqueen was used by Danny in the first challenge against Ash.
In the 2nd challenge, Nidoqueen's strength was used to help carve out a sled from Danny's slab of ice.