Charizard begins to obey Ash.
The events of Pokémon the Movie 2000 (1999) occur after this episode, despite the movie premiering before the episode aired in Japan. This is mainly because Charizard is seen obeying Ash in the movie.
Both this episode, in which Charizard starts obeying Ash again, and Paras and Parasect (1998), in which Charizard (as Charmeleon) first started to disobey Ash, were written by Atsuhiro Tomioka.
Charizard learns Dragon Rage.
The belt that Tad's Poliwrath is wearing greatly resembles to the P1 Grand Prix's belt that Ash's Primeape wears at the end of Hand-to-Hand Fighting Pokémon! Big Battle! (1997). It is very possible that Tad was born, or lives in the city where the P1 Grand Prix takes place, as he mentions it himself.