User blog comment:GameboyGabriel/What new things will there be in BTD6?/@comment-10154229-20130528224918

How about insanley fast bloons that can evade standanrd attacks, so players will have to have to have either a spike factory or a glue gunner to get through the mid levels. I'm thinking these could have multi-stage health like ceramics, but have much weaker bloons in the next layer. The other option would be to have a "Hypersonic" class of bloons to go along with regen and camo.