What is a yeerk?

a yeerk is a parisite that looks some what like a slug they infests ppls brains they have conquired theses races: the hork-bajir taxxons some learens and thousands of humans. they take totle controll of there host by wraping them selfs around there hosts brain they have also have infested 1 andalite the enamy of the yeerks

a yeerk needs to leave a host to soke up kandrona rays in a yeerk pool every 3 days

they have a unit to mark hosts here it is:

-1 phisicly unfit for inestation

-2 phisicly fit but suffer mental drawbacks

-3 great for infestation but do not breed quckly

-4 great for infestation but are hard to cunquair

-5 exalint for infestation and dosent fight back

thats basic info.