Web Caves

 is a special advanced track unlocled after beating Skull Shores. It looks like a blue rocky place with spider venom "rivers" in it. Some crystals can be seen on the rocks. There are spider webs wherever possible. It has 5 entrances and 5 exits. At random moments  in a round, an Arachnedean Bloon may appear from under one of the webs and attack the nearest tower. It is only freely playaple after beating its Special Mission.