Katst is the OBJECTIVELY WORST tetris opener that results in a t-spin triple as well as a BUNCH OF GARBAGE that you have to clean up before you get 20 spiked or something.
Created by Coolkat

Bag 1

Can be created with most bags

Bag 2

Bag 2 is used primarily to fill up the right area.
There are quite a few variations on how you can do this.

Tspin & Follow-up

After performing the T-spin, you can either perform a T-spin mini with a T block from the 3rd bag, or you can try to fill in the gap using a different method.