Sometimes Spikes

Sometimes Spikes are an item in the next Bloons Tower Defense game. They are sort of like road spikes, but when you place them, they become embedded in the ground and pop up periodically. They stay up for five seconds, then recede into the ground for five seconds, then come back up for five seconds, and so on. Sometimes Spikes cost $90, and are capable of popping a total of 100 bloons.