4/4 Bloonchipper Challenge

4/4 bloonchipper challenge is a challenge settled in the Bloonchipper factory track.

Story
A scary and foggy environment in an abbandoned factory, bloons have found it and decided to settle down a secret base , but they didn't know that a special bloonchipper tower was inside that foggy place , it detected the presence of the bloons and sended a message to the monkey base , some time later the monkeys have arrived , now your mission is to defeat the bloons.

Mission
you mission is to survive until round 50 with a 4/4 Bloonchipper, every 5 ounds the special bloonchipper will kill the your strongest tower