Elastic, stretchy cast on method for knitting, great for ribbing, almost invisible. Dubbed the "accidental method" in my head, since it was made by mistake when attempting the long tail cast on method.
Silfurfit Old Norwegian Knit cast on aka twisted German by Garnstudio Drops design. A cast on that gives a sturdy and stretchy baseline of stitches. Perfect for the top of socks, edge on hats or whenever you want very stretchy cast on.