Unfortunately for everyone, they touch the thing. Instantly, they realize what it is and what happened to these people. This hits very poorly because they come from Cannibal Titan Hell, and Reiner just found out about Bertholdt's fate.

They stare in horror. Eren's revenge trap card activates.

Reiner asks Eren to burn the essence to put whatever remains of those people out of their misery. Eren does so. Eren then points out that Slime AE is still kicking around underground; he wants Reiner to dig it up so they can kill it.

Reiner fails his will save agrees and starts digging up Slime AE so that Eren can burn it, too.