You get the Solar Monkey with the Chess Monkey by getting 10,000 pops! It will appear like a rainbow, and if you click the rainbow it will grant you the monkeys and special tracks, or if you don't have 10,000+ pops it shows how many pops you still need!
Solar Monkey Shoots out mini suns which pop through 2 layers and pierces 3 times costs $400 Path 1
Jupiterang Costs $400 Can throw out boomerangs which look like Jupiter which pop through 2 layers and pierce 3 times It now looks a bit bright brown, with its ears looking like the Jupiterangs which fit.
Neptune Rage Costs $400 Mini suns are replaced with bubbles which do the same amount of piercing and layers but shoot out 5-7 Its appearance turns a transparent blue with a storm cloud above it which is raining
Venus Bombs Costs $400 Shoots out bombs which are a pale brown colour which do the same amount of layers as a normal bomb It becomes a pale brown colour like the bombs, it is not transparent and seems to have a volcano on its tail.
Nuclear Pluto Costs $2500 Bombs throw out 8 more bombs whilst exploding and has a 2x bigger range (thrown out bombs do normal range) and bubbles become green and black, and do the corrosive glue affect. Every 1000 pops it turns into the Nebula Hole and turns back to normal every 500 pops
Nebula Hole: It does everything 2x speed.
Saturn Rings Costs $450 Suns are replaced with rings which make bloons glow if they get hit, and glowing bloons lose a layer per second. Pierces infinite times and pops 3 layers Turns brown
Uranium Uranus Costs $500 Can now shoot icy beams which can slow down bloons It is now a ice colour and transparent, with a storm cloud hailing above it
Meteorite Merucy Costs $600 Shoots out flaming meteors which do the same damage as the suns, but it also makes bloons on fire!
Mars of D.O.O.M Costs $2000 Rapidly shoots out deadly void suns which pop 4 layers and pierce infinity times.