I encountered the first single NPC that I have ever felt I had to retreat from the other day.
I popped into a USS that was very close to a star (heat leveled off at 75% or so rather than the 45% that's typical for my ship), and saw a pirate convoy of two Asps, an Anaconda, and a Viper...all wanted, with bounties ranging from 20-80k each. I engaged the Viper (who was bringing up the rear, heavily damaged him, then moved off to tag the Anaconda before it could get out of range; the Asps were getting too far a head to worry about, and I didn't want two Asp on my while I was fighting an Anaconda. After wheeling back around to finish off the Viper, I proceeded to engage the Master rank Anaconda...
50 minutes later I had expended all four charges of my SCB (which had thus far gone unused for so long that I was afraid it was past it's expiration date) and was barely able to get close enough to do worth while damage to the Anaconda who was still at 45% hull (no critical subsystems were presenting themselves as easy targets). My hull was still undamaged, but my progression against the hull of my opponent was so slow that I would have needed another hour to take him down. So, I saluted my opponent's resilience and disengaged.
I'm used to killing Elite Anaconda assassination targets in 5-8 minutes with the same loadout and no consumables used, but this thing was nuts. AI wasn't totally brain dead, it had the perfect mix of weapons (four beam turrets, two pulse laser turrets), plus could manage power distribution and maneuver like virtually no Anaconda I had ever seen. It was fast, very tough, and used it's SCBs. I found it almost impossible to stay out of it's firing arcs, and thus had to run more pips in SYS and ENG than I normally would, which seriously curtailed my damage potential.
This is not the first time something similar has happened. Ever since Gamma 2, I will occasionally run into a "Master" rank NPC pirate, who is vastly more powerful than any other NPC ship of that type I encounter anywhere else. Normally it's an Asp or a Python, but this was the first time I've seen this AI and loadout pattern converge in an Anaconda.