The item feels too powerful as a green. My suggestion is to make it red and increase the amount of crit it gives you on first pick up.

I like this idea too. Could still be a green and lower the scaling area of effect on the item and/or lowering its % damage too.

I have to second this notion, love the idea, love having it in the game but if you copy pasted this item into the legendary tier it would still be staggeringly potent once it gets going. Orders of magnitude stronger than other crit pay-offs in the game, shreds even on modded monsoon+ difficulties. 

Will do in the next patch! (the "moving to legendary tier" part I mean. it's definitely too weird for a green. you either have capped crit and a busted green item that carries the entire run, or zero crit and a near-useless item. bumping it to red tier, giving it a bit more crit chance and *maybe* slightly more damage would make it better)

On a second thought, maybe it could do with no balance changes *except* it can proc only once per second (with a cooldown debuff, kinda like bands)?

I could see the timed cooldown working too, but in all honesty it seems a touch convoluted in the sense that it interacts with crit and has a timer like the bands do.

This is very armchair of course, I just happen to like the shift to legendary rarity more. Mainly because it makes stacking less accessible. 

Promoted to Legendary tier in the latest patch!