Digimon - Tai and Biyomon Are... Idiots
When Leomon had been cursed when Devimon used 'Touch of Evil' to turn him evil, he attacks Agumon and the digidestined on the side of the mountain. When the 'camera' view goes down the mountain slightly so that you are looking slightly up and everyone, you can distinctly hear Biyomon say "But Leomon has always been Agumons worst enemy!" This clearly makes no sense, and is a huge slip-up for the writers/translators! Then, later in the episode when Tai and his digivice drive the darkness out of Leomon, Tai yells out something along the lines of "Yes, we sent that black gear right out of him!" But Tai never saw a black gear fly out of Leomon because he didn't have a black gear in him, it was the 'Touch of Evil'.
Eyes, and a DVD or video of the episode of Digimon Season One where the Digidestined meet Devimon.