Gleet Bio-Filter

Gleet Bio Filter as seen in the series, with Esplin 9466 supervising its demonstration where the unauthorized life-form is destroyed.

"As you recall, the Yeerks now use Gleet BioFilters at the entrance to Yeerk pools. They are programmed to destroy any DNA pattern other than those programmed in."

―Ax

A Gleet Bio-Filter is a device that was originally created by the Andalites, which the Yeerks had stolen the specifications to, that they had installed at all entrances to the Yeerk pool.

Ability and Function

"A Gleet BioFilter destroys all life-forms whose DNA is not entered into the computer controls. Andalite technology, of course. The Yeerks must have stolen the specifications."
"Ax, are you telling me that filter thing will wipe out any life-form except the one they program it for?"
"Yes, Prince Jake. I'm sorry to say, yes. Everything but the particular human-Controller."

―Ax and Jake

The Gleet Bio-Filter scans all life forms that go through the area and if an unauthorized life form is detected, it emits a loud alarm and blasts wide-range rays which can blind and kill any life form whose DNA pattern isn't entered into the computer controls.

When someone passes through a Bio-Filter without their DNA pattern being listed in the computer's database, it sounds an alarm, giving the would-be intruder only seconds before the device kills them via laser beams. Visser Three ordered that all Bio-Filters be programmed in order to kill intruders immediately, but the Animorphs survived (with injuries) in their fly morphs. 

Bio-Filters could scan Controllers and the Yeerk inside the Controller's head simultaneously. If a supposed host scanned negative for Yeerk infestation, they would be immediately terminated.

Appearances

• The Underground
• The Experiment
• The Sickness
• The Diversion