Heya, I found a bug with fart baby in 1.6.0, when there are two fart babies next to one another on the same column. In short: both fart babies fail to work.
When an enemy (say, a gaper) meets a Fart Baby (FB1), it pushes it on either the empty lane or the other fart baby's lane (FB2). Then the enemy should start eating FB2, which will trigger it to pushes said enemy on another lane. What happens instead is that the enemy keeps eating FB1 until it dies. FB1 tries to fart to push the enemy away, but because the enemy is on another lane, it won't move.