Foams often appear behind soaps on squares, and even behind blockers. If you look closely, they appear to be purple. The objective of foam levels is to remove all of the foams from the board. It can be removed by matching soaps on a square with foam or by using bottles. This procedure has to be repeated multiple times if it is a double or triple foam.
Each foam square is worth 1,000 points, but it can't be multiplied with cascade counts.
The foam comes in three forms: single foam, double foam and triple foam. Triple foam has a much whiter appearance and is more opaque than double foam, and single foam which is translucent.
Single foam is first seen in level 16, but will always show up when there are foam levels. This is because a double foam turns into a single foam the first time it is hit and triple foam turns into a single foam when it is hit twice. In starting boards, it is very common in the beginning but later the triple and double foams take over almost completely.
Double foam first appears in level 44. They are by far the more common type of foam in the game and they get increasingly abundant.
Triple foam first appears in level 82. They are also the common type of foam in the game and they get increasingly abundant. In the hundreds and onwards, most of the foams in the game are triple foams.
Many players consider triple foams annoying. They are responsible for making foam levels harder, due to tripling the number of hits required, including some hard to reach squares needing to reached thrice instead of once or twice. Sadly, as the game progresses, these foams become more and more common.