Portal Bloons

The Portal Bloons are bloons at always appear together. They have a 0.012% chance of appearing on any random round after round 50. The chance increases to 2% on any round if a Portal Gunner is on screen. When a bloon goes into the Blue Portal, it will come out of the Orange Portal. Bloons going into the Orange Portal will not come out of the Blue Portal. All portals disappear at the end of a round. You can try to manipulate the towers in a way so that the Portal Bloons get bloons stuck in an infinite loop. It's hard to do that, though...

Blue Portal Bloon
The blue Portal Bloon has 5 HP, and moves as fast as a Blue Bloon. When popped, it plants a Blue Portal on the ground and releases 1 Warp Bloon when popped. This Warp Bloon will go into the portal, so watch out!

Orange Portal Bloon
The Orange Portal Bloon has 20 HP and moves as fast as a Yellow Bloon. When popped, it plants an Orange Portal on the ground. It also releases 2 Warp Bloons! If the Blue Portal is planted but the orange one isn't, and bloons go into the blue one, then they will still come out of the Orange Portal Bloon.

Trivia
Portal work on any bloons! Even bosses and M.O.A.B. class bloons!

Obvious Reference...