Will since I started LUA not too long ago I have not seen this command yet:

Code:

local plr = pUnit:GetClosestPlayer() if (plr ~= nil) then

Would anyone like to clarify what it is for me?

local plr = pUnit:GetClosestPlayer()

is declaring that the simple word
plr
will get the closest player

if (plr ~= nil) then
is making sure it has a player before it does anything

Late post, but you might want to keep in mind that when you use functions such as CastSpell, CastSpellOnTarget, FullCastSpell, and FullCastSpellOTarget, they all cast the spells on the NPC using the spell, so you need to define what the target is before it starts casting. That's where this would come in to play.