In SSBB How do you get a trophy of a boss in the subspace emissary?

Answer 1

You have to fight a boss until their health is very low. Then, stall around until a bronze disc appears with the Smash Bros. Symbol on it. Pick it up, then throw it at the boss. It is very difficult to get a Trophy Stand in a boss fight, so be patient. Make sure the boss in on or above solid ground so the trophy can be collected.

Answer 2

First and foremost, go to the Subspace Emissary and battle the boss you want to trophilise (this can NOT be done on Boss batlles). Keep attacking the boss until it's health bar is about 1 cm long. After the boss is that low on health, keep resisting his/its attacks until a trophy-stand appears. Grab it, and when the time is right, throw the trophy stand to the boss. When it turns into a trophy grab it. If there is more to the level, complete it, save your progress so you can keep the trophy.