Time Portal

The Time Portal is an item in the next Bloons Tower Defense game, and costs $10000. If there are no bloons within range of one (or more) of your towers, you can place this in range. Then the tower will shoot into the portal until there are bloons in its range. There will also be a separate targeting style that will cause towers to prefer shooting into a portal if there is one in range (even if there are bloons in range as well). Any attacks done through the portal are sent either forward (to the next round) or backward (to the previous round). The portal will only send them in one direction, but the direction they are sent is randomized when you buy it. Attacks that are send forward in time to the next round will begin appearing from thin air at times corresponding to the times towers had sent attacks through the portal in the other round. Attacks that are send backward in time work in a similar way, but are able to change the past. Behind the scenes, the game very quickly runs through what would have happened in the previous round if those attacks had occurred (considering where bloons would have been, whether more or less would have escaped, and whether more or less damage would have been done to towers). Due to this, the present will appear to change almost instantaneously as long as attacks are being sent through the portal to the past - for example, you may get some lives back if bloons that had already escaped were instead popped before they could escape; and towers may get some health back if damage that had been done to them was instead prevented. However, there could also be negative effects - for example, if you had let a Nuke Bloon pass you before, but one of the attacks changed the past so that it was popped instead, all of the towers in that area will suddenly disappear. Once placed, a Time Portal will stay in place for ten rounds.