my battle system proc error shows this messege everytime it bumps into a density 1 turf. how do i get rid of it?

runtime error: undefined variable /turf/Pathways/Water/var/client
proc name: Attack (/mob/Enemies/proc/Attack)

here's my proc

mob
Enemies
var/mob/PC
ATTACKING = "false"
New()
. = ..()
spawn()
Wander()
proc/Wander()
while(src)
var/Found = FALSE
for(PC in oview(5))
if(PC.client)
step_towards(src,PC)
Found = TRUE
break
if(Found != TRUE)
step_rand(src)
sleep(5)
sleep(5)
if(istype(PC,/mob/PC))
Attack(PC)
Bump(mob/PC)
Attack(PC)
proc/Attack(mob/PC/P)
if(P.client)
if(src.ATTACKING == "false")
src.ATTACKING = "true"
flick("Attack",src)
sleep(2)
var/DMG = PSTR+KSTR
P.HP -= DMG
view(src) << "<src] attacks [P] for [DMG] damage
sleep(20)
src.ATTACKING = "false"
P.DEATHCHECK()
else
return ..()