Duelingbook Forum

https://www.duelingbook.com/replay?id=379356-52556467

I bumped into this player who made customs which work like parasyte. Taken by the inspiration i tried to make something with the same gimmick, but even by copypasting the text i cannot have the feature to shuffle into oppo's deck :/

Any hints?

If you're copying his entire effect word for word on your own card and still not getting the option to put the card in the opposing deck, then he must've used a javascript command / extension or something to enable that option for him to add his own cards to opposing decks.

Solved! Indeed wad necessary extention's help