Levels will randomly generate with burst bushes in them. The bushes look like red berries scattered around the level. It is best to have an alchemist and enforcer with you in each battle because you will want to hit the bushes from a distance to avoid them from damaging your own characters. Generally the levels that have the bushes also have "seed" enemies which are the weakest enemies in the game. You simply wait for them to get close to the bushes and when it is your turn you target the bushes to make them explode and kill the surrounding enemies.