[Derision]

in zone/spell_effects.cpp, search for case SE_ILLUSION (around line 1061)
and add a case for WOLF before the default entry. I used a size of 2 in this
example, but change it to what you want:

                                else if(spell.base[i] == DWARF){
                                        SendAppearancePacket(AT_Size, 4);
                                }
                                else if(spell.base[i] == HALFLING || spell.base[i] == GNOME){
                                        SendAppearancePacket(AT_Size, 3);
                                }
                                else if(spell.base[i] == WOLF) {
                                        SendAppearancePacket(AT_Size, 2);
                                }
                                else{
                                        SendAppearancePacket(AT_Size, 6);
                                }