Anti Assassin Trifecta solution: The Pool of Upgrades/Ice Tower BTD6

Overview
Overall, this scary monster is supposed to be a group killer. Its weakness is speedy bloons and moabs. Thus it shall be able to obliterate high clusters of rainbow bloons and under. Now, if the whom who may be reading this has not seen my other submission, that is about how instead of paths, there would be a pool of upgrades. They can be limited by either other upgrades, or just a general amount. Meaning so, These are the upgrades and limitations the ice tower has.

Statistics
Limit on upgrades per difficulty: Easy, 15. Medium, 10. Hard, 7. Impoppable, 5.

Base stats.

Attack Speed: 75

Size: Around 50x50 pixels?

Base Range: 85x85 pixels.

Basic Power: Stuns all bloons after warming up for 10 frames. in its range for 1.5 seconds. They're immune to being damaged unless an upgrade for any tower says otherwise. White and Zebra bloons are immune to this. Ceramic bloons gain 3 more health when frozen. If the bloon was popped, it gets set free.

Price: 300

Upgrades
Instant Freeze: 

Costs 400. Attack speed is now 65, and its warmup is 0.

Frostbite:

Costs 350. Requires Instant Freeze. Bloons take 1 pop of damage.

Frost Spikes:

Costs 800. When a bloon is frozen, they're frozen for 5 seconds. That, and they have 5 spikes on them. Any bloon that touches these spikes are damaged. If there are 0 spikes, bloons are set free. Attack speed raised to 150.

Shooting Spikes:

Costs 1700. Disallows Manipulative Freeze. Shoots out 6 spikes per layer of bloon that was popped while it was frozen.

Manipulative Freeze:

Costs 1700. Disallows Shooting Spikes. Freezes a bloon for 10 seconds. However, if an explosion was made on screen, the bloon is set free. Also, bloons aren't set free from damage for until 6 layers. Raises attack speed by 30.

Wide Awareness:

Costs 500. Raises range to 150x150 pixels. Also, debuffs last 1 second more.

Solid Freeze:

Costs 300. After being frozen once, bloons' speed is cut into 1/4.

From Gas to Solid:

Costs 1200. Small moabs can be frozen. However, after being frozen, they take half damage. This does not stack.

Global Freeze:

Costs 3000. Freezes all of the bloons, except for Moab class bloons for 4 seconds.

Viral Freeze:

Costs 5800. If a frozen bloon touches another bloon, that bloon gets frozen. All other effects are applied.

Frozen Tundra:

Costs 2000. Makes all bloons that come near move 1/3 of their usual speed.

Spiral Freeze:

Costs 750. Instead of having an attack speed, it has a rotating range, shaped as a spiral, moving at 59.

Cold Stare:

Costs 1500. Freezes in a straight line for 2 seconds of whoever it's looking at currently. It moves its eyes randomly.

Blood Rush:

Costs 2000. For every 20 bloons on screen, the Ice Tower's attack speed goes down by 1. So basically he goes faster when there's a big group of bloons.

Snow Dust:

Costs 1150. At about the speed of 5, a snowflake falls. It's about 5x5. If it touches a bloon, they take a stacking 1 pop per second. Including moabs.

Large Snow Dust:

Costs 1250. Requires Snow Dust. Snow now falls at the speed of 4. Also, for every snowflake on a bloon, their speed is 3/4th'd.

Cold Front:

Costs 3200. Creates 5 clouds the size of 50x50 which roam around the map, slowing all bloons underneath it by half. If they're under a bloon, they'll follow it until it is fully popped.

The Stop:

Costs 9500. All regen bloons which get frozen are popped instantly.

Trivia
I'm not sure I executed this right. I'd love criticism. So...yeah.