This block will change your level into either an ice level or a water level, depending on the ON/OFF Switch. If the switch is "ON", your level becomes an ice level. If the switch is "OFF", your level becomes a water level. This block will also enable sprite buoyancy for water level and disable it for ice level.
Demonstration Video: https://youtu.be/ecSMalNbYG0
Credit not needed, but appreciated. Just don't claim as your own.
It might be a very niche block, but I can see some interesting applications for it.
In a future version, I'd like to see variants that can toggle the on/off status so that it can work as an on/off switch itself. Maybe a version that, when the switch is off it toggles between ice on/off, and then when it's on it toggles between water being on/off. This wouldn't be very hard to do though, I imagine.