Just had a really great/frustrating run.
I had a Spriggan Assassin of Ashenzari. I cleared the Lair and the Orcish Mines with relative ease. I had a randart ring that gave rPois, rCold, rFire and +1 Int that was amazing, plus a ring of magic immunity and a necklace of warding. I had a robe of resistance, a hat and a cloak. Every available slot was filled, my hat and cloak were just generic +2s, but they were fine. I was a great utility caster with Blink, Confuse, Ensorcelled Hibernation, Agony, Summon Butterflies, Apportation, Invisibility, Repel Missiles, Ensorcelled Glaciation, Sure Blade and Regeneration. All my spells were cast at 1% chance of failure or less and most of them were powerful versions of the spells. My weapon a +4/+5 cutlass of venom was going to need to be replaced eventually, but not until I finished at least Spider, and if I needed to I could duck into Elf:1 and probably find something to replace it.
Spider isn't too hard at first I sneak up and kill Arachne, plus kill a horde of spiders and run through a cave of ice (which didn't have loot I could use so I just ran once I saw the loot instead of fighting the guardian blizzard demons). Once I got to L4 I dodged fighting Norris who looked hard for me to kill and then did the same with Kirke when I failed to sneak up on either of them. Decided to just get to L5 grab the rune and run. I find the fortress for the rune right away. Fight my way through the spiders at the door without incident. I go invis and stab all scary guards (red wasps, emperor scorpions, ghost moths) while they slept, only the last emperor scorpion even woke up and noticed what was going on. Hooray I got the Gossamer Rune!
Okay now what, I can explore around those Uniques a bit on L4 and I do the same on L5, but don't want to fight Frances so I duck around her when she wakes up. I find Nikola, and I don't have rElec, but I look at him and he has a cloak of darkness and a cutlass of electrocution... I want both of those things. (my cutlass of venom is unlikely to be useful once I leave Spider) I Agony him twice getting him quite low, and all I've lost is 8 HP and a few butterflies. I'm feeling confident, and step in for the kill. BLAM LIGHTNING BOUNCE LIGHTNING BOUNCE LIGHTNING BOUNCE LIGHTNING. "You have died..."
Sigh.