uint IdMatki = 0; //Tu wstawiacie ID matki, musicie się upewnić, że jest średnik na końcu
if (core.Client.LoggedIn)
{
    uint AttackedId = core.Player.TargetId;
    IEnumerable<Creature> creatures = core.Client.BattleList.GetCreatures();

    if (AttackedId != 0)
    {
        Tibia.Objects.Creature c = creatures.FirstOrDefault(creat => creat.Id == AttackedId);
        
        if (c == null)
            AttackedId = 0;
        else
            return;
    }
    Tibia.Objects.Creature Creature = creatures.FirstOrDefault(c => c.Name == "Slime" && c.Id != IdMatki);
    if (Creature != null)
        Creature.Attack();
}