The Alien Life Cycle (Apocalypse)
Well, this is the next step up from The Alien Genetic Structure. So naturally, this means you get Toxin B! Yay! Practically night and day compared to Toxin A, Toxin B can eliminate your foes MUCH quicker. Hooray for quicker annihilation! However, for you to get this toxin, you will need the following: Brainsucker Pods, Brainsucker, Brainsucker Autopsy, Multiworm Egg, Multiworm, Hyperworm, Chrysalis, and the Chrysalis Autopsy. Once you have these, you can research Toxin B!
Official Entry: "It is clear that the Alien life cycle is an extremely rapid sequence of changes. The eggs always develop into Multiworms which then give birth to Hyperworms which form a Chrysalis. At this stage the genetic variation produces a variety of Alien types which develop inside the Chrysalis. The whole process from the egg hatching to emergence from the Chrysalis only seems to take about ten days, provided that there is an adequate supply of food. Fortunately these life forms do not survive very well in our world and it is unclear how an invasion could be successful."