[Armored Tower - Upcoming Changes]

I would expect similar to the lost wanderer, every 3 seconds the tower casts a spell that applies the shield to a single entity (or a small number of them). If so, this should be explicitly stated in the description

[Community Map Challenge #4: “Lyr’s Distress Call” until 21st February 2022]

no special prize for the fastest pure frost timing? 😛