They become easier to handle once you spend a bit of time with Crate of Entertainment Superboss 
(He summons non-stationary Pets that do the same thing as Crystals but with fire projectiles that 1 shot you and if you kill a pet, they multiply like Kubacabra)
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Btw, if you or anyone else for that matter are interested in more Mogdrogen devo based builds, there is also this: Pet Conjurer - Moggy the Puppy!
It was made Pre FG and hasn’t really been updated, but I can do so on request if there is enough demand 