Melissa is a strong Pokémon trainer who managed to qualify for the Kanto Pokémon League Tournament. Melissa is actually a male character in the Japanese version.
Kanto Pokémon League Tournament: Round 4 - Grass Field - Vs Melissa
It down to the last Pokémon of both Gary and Melissa to see whom would proceed to the final 16 of the Kanto Pokémon League.
Towards the end of the battle Gary's Nidoking faced off against Melissa's Golem and both Pokémon looked tired. Gary ordered his Nidoking to use a Horn Attack, but Golem anticipated the move and managed to grab onto the horn and maintained a firm grip on it. In the final move of the round Golem used Seismic Toss on Nidoking, smashing it into the rock arena. When the dust settled Nidoking had been eliminated and Melissa managed to progress into the final 16 of the tournament.