Board Thread:Versus Battles/@comment-27044517-20180504235644/@comment-27044517-20180508045258

Yeah.

Frisk didn't swing at the SOUL.

Also

"When a Boss Monster dies, their body turns to dust; however, their SOUL, in an upside down heart shape, lingers for a few seconds before shattering."

It's more likely THAT as the exact same animation happens with both Asgore (who is a boss monster) and in the Neutral Route.