Bomber (known as Exploder in Lemmings 2: The Tribes, and in the original PC demo) is a skill that can be given to a lemming. It is the third of the eight skills available in Lemmings, as well as the Classic Tribe in Lemmings 2. When a lemming becomes an exploder, a countdown appears above its head and it continues what it was doing for five seconds before it explodes, creating a hole in the ground. In Lemmings, if the lemming is falling when the countdown expires, it will explode straight away; otherwise, it will stop for a moment before exploding. This is the only non-permanent skill that can be assigned to a lemming who is not on the ground. In some fan-made engines, like SuperLemmini and NeoLemmix, the countdown is removed from the exploder. In these, the lemming will explode immediately after having the skill assigned to it.
In Lemmings: The Official Game for mobile devices, bombers are the only way to remove staircases left by builders, and can in fact only be used for that purpose. Due to the tile-based nature of that game, a Walker going into a tile with the bomb order will automatically become a Blocker to start the countdown. If the command was given in error, the Bomber can be rescued by reverting it to a Walker before the countdown ends. Both of these actions cost no energy.
In Lemmings 2, outside of the Classic tribe, exploders will create a knockback explosion that sends all other lemmings within a small radius flying, and stuns them temporarily. In addition, these exploders will detonate as soon as their countdown expires, regardless of whether or not they are falling. In L++, knockback exploders and regular exploders are available as separate skills.