Once they're close enough to the essence, they will see that the surface of it reflects a young man's features. Then there's a young woman, an old man and several other forms passing through the reflection. The very essence seems to be formed from several people.

If either of them decide to touch the essence they will see the final moments of whoever is reflected on the surface of the essence. Of being consumed by one the Weapon Slime slowly and painfully and eventually being turned into this essence and mixing in with others.

The essence can be picked up and put in a jar, but there's nothing that can be done for the people anymore. Best solution might be just to let the soil consume it.