Adhesive Film is a new item introduced in Pokemon Genesis that sticks to the original holder and cannot be removed until six months after it is captured. It prevents the holder from being traded. Once it is removed, it is placed in the bag and can be used a "Dry Film" which increases the holder's Attack, Special Attack, and Accuracy.
The use of Adhesive Film in Pokémon Genesis caused a large amount of criticism. It was attached to every Legendary Pokémon in the game, meaning that people who wanted to trade their legendaries would not be able to for six months. There will be no Adhesive Film on the Legendaries in the new Expander Disc coming soon.
Adhesive Film was created to prevent absurd trades in the Global Trade Center (i.e., Giving a Level 100 Palkia for a Level 1 Paras) for at least six months. Nintendo hoped this would teach a lesson for people who conducted poor trade deals, but it instead caused an uproar among fans.