[cavedude]

This code causes a zone crash when the player uses an invis spell and has no pet up. Here is the output:

#0  0x080fdc43 in Mob::BuffFadeByEffect(int, int) (this=0x0, effectid=22,
    skipslot=-1) at spells.cpp:2726
#1  0x080c8757 in Mob::SetInvisible(bool) (this=0x8586490) at mob.cpp:395
#2  0x0819fcd5 in Mob::SpellEffect(Mob*, unsigned short, float) (
    this=0x8586490, caster=0x8586490, spell_id=42, partial=100)
    at spell_effects.cpp:439
#3  0x080fd5e7 in Mob::SpellOnTarget(unsigned short, Mob*) (this=0x8586490,
    spell_id=42, spelltar=0x8586490) at spells.cpp:2602
#4  0x080fa4a5 in Mob::SpellFinished(unsigned short, Mob*, unsigned short, unsigned short, unsigned) (this=0x8586490, spell_id=42, spell_target=0x8586490,
    slot=1, mana_used=0, inventory_slot=4294967295) at spells.cpp:1466
#5  0x080f91c6 in Mob::CastedSpellFinished(unsigned short, unsigned, unsigned short, unsigned short, unsigned) (this=0x8586490, spell_id=42, target_id=263,
    slot=1, mana_used=0, inventory_slot=4294967295) at spells.cpp:923
#6  0x080f7240 in Mob::SpellProcess() (this=0x8586490) at spells.cpp:132
#7  0x080f725e in NPC::SpellProcess() (this=0x8586490) at spells.cpp:139
#8  0x080df229 in NPC::Process() (this=0x8586490) at npc.cpp:521
#9  0x080bd5c7 in EntityList::MobProcess() (this=0x82b0240) at entity.cpp:462
#10 0x080e3676 in main (argc=0, argv=0xbfffefe4) at net.cpp:481