I was thinking about underused exotics and Monte Carlo came to mind. It is one of my favorite looking and sounding exotics in the game but all it does is recharge your melee faster, and it needs somthing to make it unique. And then I thought about the knife thing at the end of the gun and I came up with this idea for a catalyst. Charged melee kills grant 3 stacks of Monte blade and uncharged melee kills grant 1 stack of Monte blade. When Monte blade reaches 5 stacks you unlock the ability to do a super powerful melee with your weapon. Getting a kill with this melee will grant you 2 more stacks of monte blade, and increase your melee recharge rate for a short time. Dealing damage with the melee will increase your chance for your melee to recharge upon a final blow. This could have a few adjustments just let me know what it could have. I think this would have great synergy with a one-two punch shotgun and/or top tree arcstrider.