Supernova Intensity Mutator

Infuses your weapons with the unstoppable power of a supernova explosion, boosting attack by 50%.
Stolen from the experimental facilities of the hulking (unlockable non- player enemy from temporary mission)

50% is a hell of a lot, considering supernova explosions are already going on in your ship for energy.

That would be why you would have to do the the mission, then kill the NPC. And notice I said "hulking" which implies that the NPC is very challenging.

We have one of those thingys in our legion already

Seriously though, 50% is wayyyyy too much unless maybe it lasts 5 minutes.

Or has some large draw back.

This artifact should only be available in my legion...

Going with that:
It needs to be something "above" supernovas, because we can already contain supernovas. Gotta be by the logic of something much more powerful.

In any case, possible draw backs are:
After this buff expires, you enter a non-dispellable debuff state
Reduce energy regen for certain duration
Cause damage to your ship and/or modules

But yeah, 50% boost needs to have draw back, very short and/or restrict action types

Agreed. How about a Gamma Ray Burst for example? far more powerful than a supernova..

Other drawbacks could include:
Destroys one/several weapons (overcharges it so it explodes, would have to build a new one)
You could have to uninstall some other modules while its in effect? (for example defense)
plus more.

Just set it so the buff is similar to an ability, where you can activate/deactivate it, but whenever you choose to have the buff active either all recharges (shield and energy) are stopped due to strain on the ship to support the weapon systems, or you take gradually increasing damage every 30 seconds or so due to having an active supernova channeled through your ship.