Cockroaches

Cockroaches are a pest that appears in The Sims and The Sims 2. They are spawned if a lot is dirty, and they will randomly move about the lot, further decreasing Room or Environment score.

The Sims
In The Sims, having roaches on a lot can cause considerable distraction, as Sims and visitors will autonomously "Freak Out", neglecting their motives in order to go and stomp on roaches on the other side of the lot. However, roaches can easily be killed by instructing a Sim to spray them. If the Sim is in a good mood they will automatically spray every group of roaches on the lot, until there are no more roaches left or their mood goes too low. The maid will also spray them, and if Unleashed is installed, cats can hunt them. Once killed they disappear and leave no trace. Roaches in The Sims can pass through walls, and so may be able to get to places that Sims can't.

The Sims 2
In The Sims 2 roaches are more difficult to get rid of: while Sims can sprays them, the maid will not, and spraying by Sims is not as effective as calling an exterminator. In addition, going near roaches carries the risk of flu, so hiring an exterminator is overall the safest and most effective option. However, roaches that have been killed by either an exterminator or a Sim will remain in a pile that decreases Environment score as much as living roaches, and must be cleaned up: this can be done by either a Sim or the maid.