RPS Monkey

First of all, RPS is short for "Rock, Paper, Scissors", so this is a Monkey that plays Rock, Paper, Scissors. Before each round, it will choose either Rock, Paper, or Scissors at random (equal chance of each), and that will affect its attacks for that round.

If it picks Rock, it will throw rocks which pop one layer from one Bloon, but also inflicts 5x damage on Bloons which take multiple shots to pop (Ceramics, Blimps, even Bosses), and it can shatter Leads and similar Bloons.

If it picks Paper, it will throw paper aeroplanes which pop one layer from three Bloons, and have homing capabilities (like Seeking Shurikens).

If it picks Scissors, it has a tiny range (0/0 Tack Shooter), but attacks nearby Bloons very fast, popping five layers a second.

It would look like a monkey (obviously), but either holding a rock, a paper aeroplane or a pair of scissors. I'm also too lazy to think up how its appearance changes with each upgrade. :P

Quicker Attacks
All attacks get a rate-of-fire increase!

Price: $250 on Medium.

Details: It's attack rate increases by 1.5x.

Increased Odds
You can now choose a specific attack, and it will have a better chance of using that attack!

Price: $500 on Medium.

Details: The chosen attack has a 60% chance of being used, all other attacks have a 20% chance.

Chosen One
If you choose one attack, it will always use that attack!

Price: $650 on Medium.

Supercharged Attacks
All attacks become super-strong!

Price: $2,500 on Medium.

Details: Rocks are larger, pop five Bloons each and deal 10x damage to Ceramics, Blimps and Bosses; Paper Aeroplanes are longer and thinner, popping nine Bloons each and travelling faster; Scissors pop Bloons three times as fast!

Triple Threat
Tier 5 Upgrade: It somehow multitasks and uses all three attacks at once!

Price: $7,500 on Medium.

RPS Pro
This pro is great at popping Bloons, one in ten shots does double the damage!

Price: $350 on Medium.

Lucky Shot
Although it doesn't have Camo Detection, it can now hit Camo Bloons by accident.

Price: $350 on Medium.

Details: It won't target Camos, but it can hit them by accident, like most (if not all) Towers in BTD4.

Rock, Paper, Scissors, Lizard, Spock
Ever heard of a variant of RPS which has a Lizard and Spock in?

Price: $1,750 on Medium.

Details: Lizard makes it drop a Lizard every ten seconds, which crawls towards Bloons and eats them. It can't eat any Bloon which takes multiple shots to pop or Leads. It can eat lots of Bloons, but once the eaten Bloons equal an RBE of 50 or more, it will disappear. It can eat Bloons with an RBE of more than 50, but it will make the Lizard disappear instantly. The targeting system of the Tower affects what Bloons the Lizards will attack.

Spock on the other hand will stop it attacking, but will grant Camo Detection to all towers in its radius, and all those Towers gain 1AD and their health will be restored to maximum, as well as increasing their max health by 50%. These buffs will last ONLY when the Monkey is using Spock.

Combination Ability
Combination Ability: Uses a super-powered attack with all five regular attacks boosted and combined!

Price: $5,000 on Medium.

Cooldown: 30sec.

Details: It fires a large paper aeroplane (which pops two layers from 25 Bloons with infinite range) which carries three giant lizards (each can eat any non-Boss non-Blimp Bloons up to a max RBE of 100) that are dropped off when the paper aeroplane reaches its pop limit. The paper aeroplane can also inflict 20x damage on Blimps, Bosses and Ceramics, pop Leads, AND it has camo detection. Lastly, four pairs of scissors will orbit around the Tower for five seconds, dealing damage to Bloons that touch them (similar to orbital glaives).

Team Combination Ability
Tier 5 Upgrade: Improved Ability: When the ability is activated, every other attacking tower within the tower's range will use the super-powered attack too!

Price: $30,000 on Medium.

Details: Basically, each tower in range uses the attack as well as the tower itself. Very effective if it's near a group of other towers.