Ok so here’s what I put:
!editcom !slap $(eval user="$(user)";touser="$(touser)";responses=$(urlfetch json PASTEBIN);responses[Math.floor(Math.random()*responses.length)])
(PASTEBIN is replaced with the proper url, ZvVsTuMU)
and when I do it, nightbot just returns random letters of the alphabet, no matter if I put !slap Mark or just !slap