My idea is make the Red chain a Berserk Gene key item replacing the Nugget in Cerulean water, that turns on or off a flag that can be read from the game to use the Spelon berry to works exactly like the old Berserk gene, a flag that turn off automatically when you enter into the union room or the linked battle frontier to avoid glitches if you fight against games that don't have the hacked item (and this is easy to do, you have only to add to clear the flag in the script to enter into) and I want to know where is the major difficulty, to do the Spelon Berry working like the Berserk Gene (have to be like Swagger) or working like it only if a flag is turned on? E-card berries replaced the placeholder Enigma Berry, Why a Spelon Berry couldn't be a "placeholder" to overwrite it only if a flag is set? Or maybe instead of a flag, The key item could do an e-berry like effect? Make the Spelon berry something like an e-berry? And erase the e-berry when you enter in the union room?