I fixed the problem (I was using the wrong MPQ file).
I have this script now on Trinity's Eluna engine but it doesn't seem to work. I'm not familiar with Eluna and the methods and hooks are different so I'm not sure if this is right. I couldn't find any methods in Eluna similar to HasAuraWithMechanic so I'm not sure what else to use.
function Tenderizer(event, player, spell, skipCheck)
local Caster = Spell:GetCaster()
if (spell:GetEntry() == 80914) then
if (Spell:GetTarget():HasAuraWithMechanic(12)) then
Caster:DealDamage(Spell:GetTarget(), 300, 0, 0, 80914)
else
Caster:DealDamage(Spell:GetTarget(), 150, 0, 0, 80914)
end
end
end
RegisterPlayerEvent(5, Tenderizer)