What was the most tense experience you had in the game? *Potential spoilers*

Warning: Novel sized post ahead. TL;DR version at bottom of post.

Mine happened earlier today on my 2nd playthrough. Early on I leveled up pretty much just strength and skill so I could use the Black Knight Halberd. I had 14 Vitality when I headed into The Catacombs.

I jumped down to the secret bonfire, and proceeded to the boss. However, I forgot not only the most efficient route, but the location of one of the Necromancers. I attracted the attention of two immortal skeletons, right before falling into the hole where the Black Knight is.

I had around 1/6th health at this point. I backstabbed the knight right as the two skeletons fell down besides me. I temporarily KO'd them, then finished off the knight before they revived. I hopped down to the wheel skeleton area.

I attempted to find the blacksmith, not knowing there was an unbreakable wall between him and me due to not triggering the cutscene. While warding off the immortal skeletons (Who could kill me in 3 hits) I got randomly attacked by the wheel skeletons. Somehow I always faced the right way, with my shield up, and slowly diminished their numbers.

While all this was occurring, I was getting attacked by another immortal skeleton who had glitched and all that appeared was its eyes. It also appeared to be floating/flying since its eyes were a ways above my head, although it could still attack me.

Finally I defeated all the wheel skeletons, and ran away from the immortal ones. I went into the boss arena with 0 Estus Flasks, and thus couldn't heal the fall damage upon entering the arena. I managed to take off 1/3rd of the bosses' health before it disappeared. It appeared right next to me, I finished it off, then teleported back to the secret bonfire while breathing a sigh of relief.

TL;DR version: Survived attacks by a Black Knight, immortal skeletons, (And a glitched one) bonewheel skeletons, and the boss; all with very low health.