Caseydia
Ace Trainer
When was completing the pokédex Ash's goal? Anyway, I think the writers purposely had Ash scan Koffing so that they could introduce it to younger viewers who never played R/B/Y/FR/LG
Makes sense but Ash should have already completed that portion of his Pokemon full of old pokemon. It just makes Ash seem dumber than he is by older kids(adult) who have been watching the show for years.