Wasteland 3

This achievement is done in the Mycology Lab on the Research Level. Inside the lab you will see 3 computers placed beside tables, each with their own mushroom on it. Collect the three mushrooms: the Panther, Destroying Angel, and the Horse mushrooms. The respective computers will have information on how much radiation and cryogenics to give each mushroom, but here is the list I collected:

Panther: 15 miliseconds radiation, 10 miliseconds cryogenics

Destroying Angel: 40 miliseconds radiation, 20 miliseconds cryogenics.

Horse: 10 miliseconds radiation, 20 miliseconds cryogenics

With the three mushrooms in hand, head over to the computer on the eastern wall and interact with it. Deposit the mushrooms one by one and apply the proper amount of radiation and cryogenics to each one. Then just consume the holy variants of the mushrooms you receive in return and the achievement will pop.

Note: I had one ranger eat all three. I do not know if the achievement will work if you distribute the mushrooms to multiple rangers.