@SlackHQ 's "what are the nightmares that haunt you" is not an icebreaker for people who have PTSD with actual nightmares, it's a trigger! 
This is an icebreaker in "snack", #slack 's break out room "feature"!
#inclusion
This doesn't sound like a native Slack feature. Do you see an 'APP' tag next to the avatar of these messages? If so, it's coming from a third-party app that someone has installed on your workspace.