Lifestealer is a first-eraShadowtower that can knock backsmall-sizecreatures. Its non-upgraded damage is quite good: up to 42.5 damage per second for a single target/65 damage per second total (in a 5m radius). Upgraded, it increases to 45 single/70 total and 50 single/75 total for Lifestealer I and II, respectively.
The big drawback of this tower is that each shot reduces its own life, though mitigated by it's regeneration ability. It can fire once every two seconds, with each shot reducing its life by 50. With it's regeneration of 5 life points per second, the tower self-inflicts 20 DPS. This is not so bad, except when compounded with enemy damage. Unfortunately, repairing is not too helpful, as it doesn't really kick in until the tower is out of combat.
It is best compared with its sibling card, Phase Tower, which is considered by some to be a good alternative. Phase Tower costs 20% more, has less DPS (36 single/53 total), less life, and lacks knockback, though it's relocation ability gives it versatility. Of course, it is also not self-destructive.
Note: Despite knocking back Small Creatures, this is more of a hindrance than an asset. Due to the small AoE of the knockback, it tends to waste damage by only hitting a single squad member.
Every 2 seconds, tower fires a painful shot that deals 85 damage to enemies in a 5m radius around its target, up to 130 in total. Every shot reduces the tower's life points by 50. Tower will no longer attack once its life points have been reduced too far. Knocks back small units.