Slows Bloons down even after they thaw out!
~ BTD 4 description
Makes the bloons so cold that they move slowly even after thawing out.
~ BTD 5 description

Permafrost is the second upgrade of the Ice Tower. It allows Bloons to stay slow once they have been unfrozen. They can be upgraded into Snap Freeze. In BTD5, it's the 1st upgrade of the second path. These are also one of the cheapest upgrades in BTD5, next to Sonic Boom, and Extra Range Darts. If combined with sabatoge supply lines and glue it will make the red bloon slow as a ZOMG

BTD3 CostsEdit

  • Easy : $215
  • Medium: $255
  • Hard: $270

BTD4 CostsEdit

  • Easy : $85
  • Medium: $100
  • Hard: $110

BTD5 CostsEdit

  • Easy : $85
  • Medium: $100
  • Hard: $110
  • Impoppable: $120*

*Only available on Mobile/Steam