Viral Frost

"Frozen Bloons freeze other bloons that come into contact."

- BMC Steam description

"Frozen bloons freeze other bloons that come in contact. Can detect camo."

- BTDB Steam description

 is the final upgrade of path 1 for the Ice Tower in Bloons TD 5.

Whenever Bloons touch frozen Bloons, they also get frozen, and so on, spreading it like a virus, hence the name "Viral Frost". The viral freezing effect also affects White Bloons and Zebra Bloons. In BTDB Mobile, Viral Frost also can pop and freeze White Bloons, Zebra Bloons, and Camo Bloons.

The main use of this upgrade is to pass the freezing effect on through lines of bloons out of the tower's range and onto camo bloons. Viral Frost does not spread Snap Freeze. This upgrade works well with Glaive Riccochet combined with Sonic Boom as both work by contact with other bloons. This, combined with a Glaive Lord placed as furthermost left or right at a corner (Arctic Wind slows down the bloons to help Glaive Lord deal more damage), can decimate a whole bunch of closely packed ceramics (although Sonic Boom is required for popping frozen bloons).

The upgrade picture is an Ice Monkey in a blue coat surrounded by snow.

Summary
Viral Frost is often unnecessary of a purchase, seeing as Arctic Wind already slows down bloons substantially and actually clumps the bloons up better.

Tips

 * Try adding this with Glaive Ricochet to give the Boomerang Thrower with a much better synergy.
 * It's worth taking note that Viral Frost's viral freeze won't affect White or Zebra, even when given an MIB.

Trivia

 * Viral Frost is one of the few upgrades from BTD5 to not return in any form in BTD6.
 * Lightning Bolt, Summon Whirlwind, and Tempest Tornado were moved to the Druid, but were renamed.