You can call it acatales for short if saying acapella is too much and you’re lazy like I am.
This is a Undertale Au about Using singing to power up magic For combat. Instruments like Electric guitars, bass with a rock, metal style is Fight mode. The monster and or human has to be singing though for this to work. The only Time instruments are allowed anyway is if the Human or monster is mute. Like Frisk, for example, They are mute so if they are showing mercy you will hear a soft instrumental. But other than that You only have everyone who can speak Sing in acapella. This Au was Created by CandyTrickster on Tumblr.