Here's what happened when 12 random people took turns drawing and describing, starting with the prompt "Underpants Sans (Google it)".
UnderPants Sans!Swap by alecoronel9 on DeviantArt
Sans Undertale - Drawception
Finally Mail!! : r/Undertale
Finally Mail!! : r/Undertale
Sans (Underpants), 735q4e87 Wiki
Sans (ut) - Drawception
Underpants Sans Style Conversion with Undertale Sa by Abbysek on DeviantArt
Finally Mail!! : r/Undertale
UnderPANTS (not undertale) - Drawception
Sans In Briefs by ThePokemonTeller on DeviantArt
Undertale hand drawings - Underpants Sans SANESSS Creator: Sir Pelo