How to play this dungeon:
Shelob is a powerful creature and the horror she creates is one of her most powerful weapons. She is not a staunch fighter and prefers a clandestine attack to open combat. Heroes who enter her lair will have to do Wisdom throws at regular intervals, otherwise panic and fear will slowly overwhelm them. Shelob knows how to use this to her advantage.
She herself can move quickly and easily in her cave system through the holes that can be seen in the walls. (So to speak, a cave system in the cave system. Heroes can also try to enter them, but the paths there are steep climbing sections and Shelob’s advantage is even greater there)
With these holes she can move quickly through the walls and across the map. She waits behind corners, jumps out of holes and will try to stun individual heroes and then quickly pull them into one of her holes and then bring them to her pantry. So the group decimates faster and faster, some will split up and the hunt will be even easier.
It is also possible to add a character like Gollum. He will actively try to mislead our heroes. He distracts them just before Shelob attacks or imitate the screams of a kidnapped hero to lure our remaining heroes in the wrong direction.
Our heroes have the task to traverse the dungeon, not to lose anyone and to escape the recurring attacks of Shelob. If they manage to reach the exit, Shelob will launch a final face-to-face attack.
In addition, you could add smaller spiders, which also start smaller attacks in the dungeon and support Shelob.