Board Thread:General Discussion/@comment-30664268-20170429210906/@comment-30664268-20180226025056

UndertaleFanatic443 wrote: Give the goat one of those 6 human SOULs! Especially a green SOUL, that would really fit him. :D He used the souls to break the barrier.

Absorbing souls uses them.

Proof is that Sans says that the souls disappeared in Neutral, so their gone.