We have the bone callers to summon friendly skeletons, and with the recent addition of the merfruit I thought it would be cool if there was a third usage for it.
Right now, uncooked heals you for a mango's worth and cooking it enchants it to hide your mermaid.
I think that if you go beyond just cooking it and burn it, the merfruit gets corrupted, and summons a gang of friendly sirens around your ship
Just as the skellies can help you on your ship, the sirens could help with boarders who retreat into the water / get knocked off.
Potentially it could summon ocean crawlers if you're on an island when you eat it, to make it not as niche.
