Bloonberry Bush

"Plant this fast-growing bloon killer right on the track. Loses a thorn for each bloon popped, but grows 5 thorns between each round (up to 200). You protect it, it'll protect you."

- Official BTD5 Description

A  is a Special Agent in Bloons Tower Defense 5. Once placed, it acts as a regenerating spike trap until the game is over. It originally has 10 thorns and grows five thorns (10 in Bloons Tower Defense 5 Mobile) per round, for a maximum of 200. If the player has the Premium Upgrade Tack Awesomizer activated, the bush will be able to pop 400 Bloons (with each thorn be able to pop 2 bloons). Even if all thorns are destroyed, it will still remain on the track, but it won't be able to pop any bloons until the next round. Lead Bloons will destroy all the Bloonberry Bush thorns completely.

A Bloonberry Bush is not an ordinary tower, being more like a road item, and requiring 50 to purchase. They can only be used once, and remain on the track for the length of the entire game. It can be used as an alternative for spending money on Road Spikes or Spike Factories.

Strategies
You can "cheat" the Bloonberry bush by placing it on the track, then saving the game at the last round before freeplay. Strangely, if the bloons finally did manage to take away all the thorns of the bush, and rush to the exit as game over, when you come back to continue the game, the Bloonberry Bush will have no thorns, like last time, but it will still remain on the track.

Although the Spike Factory is probably the better choice than the Bloonberry bush as it can produce a lot more spikes which can also be upgraded to pop Lead and Frozen Bloons, the Bloonberry Bush has spikes that stay on the track forever and do not disappear between rounds.

Trivia

 * A fully grown Bloonberry Bush can pop the outer layer of a M.O.A.B.
 * The Bloonberry Bush grows (and degrows) depending on its thorns.
 * The Tack Awesomiser Premium makes the Bloonberry Bush pop twice as much even though it doesn't have any kind of Tacks on it.
 * The word "bloonberry" is a pun on blueberry.
 * Surprisingly, placing and or upgrading a Monkey Village near a Bloonberry Bush may make it seem like the amount of spikes have been reset, but really it has added its max 200 to the bush (though it seems small). Do this repeatedly and it will keep adding 200 spikes. If done enough times, it can (FLAWLESSLY) destroy a whole Z.O.M.G. and its other children but you must repeatedly keep selling and placing the Village. (It has been tested)