TPK is a common role play term for a total party kill, where all the characters are killed (ending the adventure). While a TPK is generally a bad thing, the threat of a TPK can increase the thrill of overcoming or surviving an encounter.
TPK encounters are encounter templates designed to throw a serious curve-ball at your players.
Each encounter is designed to scale with the party and uses a degree of randomisation in the presentation. Thus, each post will differ for each GM. There is a large set of custom template tags and a sizable PHP class backing this up.
Currently, I have only written TPK encounters for Pathfinder but they should be usable with any DnD 3.5 compatible ruleset. It should require only minimal changes to work with, for example, Star Finder.
I intend to expand the encounter collection to include S3 games (a system I am designing) for both the S3 Mad Science and S3 High Fantasy settings.