I have not seen any posts yet explaining this device but I may have missed it, but at any rate here is what I figured out on my own. It is not a way to recreate vanilla spawners as I first believed. It is in fact a device like any of the other ones in Ars Magica, You need to power it from a dark essence battery, which means using it eats up your dark essence but you can use and reuse any of the captured souls you have in a phallic to change what mobs it spawns. The phallic goes in the spawners one inventory slot and then you connect dark essence to it like any other device in Ars Magica. It does require more dark essence then you can harvest from the spawned mobs but that keeps it in balance. However, you can switch out the phallic at any time to spawn specific mobs you need for other items or drops. I do hope this helps, and if I just missed the answer to this then I hope reposting it here does not upset anyone.