Spiked Wall

"Simple: Place this Special Agent on the track, and nothing - not even MOAB-class bloons - can get past. Spiked Wall pops every single bloon it touches, but it comes at a whopping price."

Cost
Spiked Wall costs 26000 Monkey Money and requires 130000 Monkey Money to unlock the Spiked Wall Pro

(26000 x 5 = 130000).

Spiked Wall Pro
"Pro Upgrade - Round Skipper Special Ability! Since you have spent heaps of Monkey Money and have probably died of boredom from waiting until that long round has ended, we think you deserve a little treat. Just click on that Special Ability button and the current round will end."

After 5 placements, you will unlock the Pro version. The Round Skipper special ability takes 100 seconds to cool down.