| Team | Alien |
| Stage | 1 |
| Build Points | 8 |
| HP | 125 |
| Abbreviations | tube |
| Name for Binds | acid_tube |
| Build on walls | Yes |
Acid Tubes are the primary alien defensive structure. When approached by a human, they eject lethal acid in all directions, even over other structures. Acid Tubes may be built on walls and ceilings in addition to the floor. The closer an enemy is to an Acid Tube, the higher the damage the enemy recieves.
Effective Placement: Acid Tubes are ideally placed out of sight due to their low health. Placing them on walls and ceilings keeps them out teammates' ways. Spreading them around on the floor considerably slows the steps of humans and makes it hard for them to get through. The limited range of Acid Tubes means that they should be placed around entryways. Placing two or more near the Overmind can prevent Painsaw attackers from disabling the whole base.