geez napa, they call it "doing a napa" for a reason bro,
for a beginner regex is never "ez".
would be nice if some explaination was added to what and how your script works (for noobs or non regex users)

!slap (nick)

on *:TEXT:!slap *:#: { 
  if ($2 == $me) { .msg $chan No!  }
  else { set %slap $rand(1,8) | $slap.action $chan $$2 }
}

; return the string to msg the channel and grab the random object using $gettok
alias slap.action return .description $$1 slaps $$2 around a bit with a $gettok($slap.objects,%slap,58)
; the random objects using ";" $chr(58) as the seperator
alias slap.objects return large trout:large pig:large horse:large cat:big mac: large dog:computer:stloen car

also its late here but i cant see why (unless its bracket placement)
the msg $chan NO! doesnt work.

NOTE: i didnt test it myself