Board Thread:General Discussion/@comment-26680716-20160501054031/@comment-26114304-20170210100159

Diamond655 wrote: Okay, so, first off, Sans attacks first, right? Every other battle, you attack first, and your opponent's boss theme plays(if they survived that first attack, anyway). So, if you're not the one to attack first, who's theme plays? Yours.

Secondly, Sans already has a battle theme. Song That Might Play When You Fight Sans. It never appears, but if Sans already has a battle theme, he wouldn't need another onet. If Megalovania was Sans' theme, there'd be no need for STMPWYFS to be composed at all - unless Toby just felt like trolling players. So, this means that Megalovania should be your theme.

Flowey also attacks you first, both in his normal form and his Photoshop/Omega form.

Also, there are other characters that have more than 1 battle theme:
 * Undyne: Spear of Justice, Battle Against a True Hero
 * Mettaton: Metal Crusher, Death by Glamour, Power of NEO
 * Photoshop Flowey: Your Best Nightmare, Finale
 * Asriel: Hopes and Dreams, Burn in Despair, SAVE the World, (technically) His Theme