XCOM 2

The Proving Ground is a facility that allows you to create experimental items, such as ammo or grenades and specialized suits of armor for your troops. To build it, you must first collect the corpse of an ADVENT Officer (random chance to drop every time an officer is killed) and then have Dr. Tygan perform an autopsy on it from the Avenger's Research Lab. The cost of the Proving Ground is $100 ($125 on Legend), it requires 3 power, the build time is 7 days and the monthly upkeep is $25. It will take a few days to create an item (less if you have an Engineer staff the facility) but you do not have to suspend other research projects to do this. To build an experimental item, you will need an Elerium core (which is an uncommon drop from enemies and can sometimes be purchased from the Black Market). You can choose the category of experimental item you want to create (Ammo, Grenade, Armor, Heavy Weapon or Powered Weapon) but the actual item you receive is chosen at random from a list of several possibilities. You may need to research the same experimental category several times before getting the item you want. This trophy will pop after the first experimental item has been created.

For a list of experimental items: LINK