Board Thread:General Discussion/@comment-4504826-20160412211101/@comment-27907368-20160414080548

We're unsure how the battle mechanic itself functions. None of our meta characters care to talk about it or how the bullet board looks to the monsters.

Therefore, it is unknown whether bullets are connected to magic ability or are just a symbol for an attack. Attacks are also used to communicate in game - here's looking at the red exclamation points as well as the grey messages given by Napstablook and Mettaton.

Sorry I can't give you a definitive answer. T_T For what it's worth, Flowey plus a ton of human SOULs doesn't make much sense either; he just starts tripping on power and we roll with it.