I got a pretty cool idea for a Nazo no Murasame-jo Assist Trophy after playing the game a bit.
Meet the Maiden (Or Damsel or whatever else you want to call her.)! In Nazo no Murasame-jo, you can rescue Maidens who have been kidnapped to get an extra life. However, when examining the bag that they're being kept in, you may be surprised to find that it's not a Maiden at all, but rather a powerful demon that will chase you around the castle. As an Assist Trophy, this bag would appear before showing either the Maiden, who would heal the summoner of all damage that they have received, or the demon, who would attack the summoner and likely KO them. Finding out that you've summoned this Assist Trophy would make the match really tense for a moment or two, since it would either be extremely helpful or absolutely disastrous. It would be enough to completely change the way the match is going in either fighter's favor.
What do you guys think? Do you like the idea? Or would it maybe be better off having the bag as an item that you can choose to take the risk of opening?