Urza/AskUrza.com

refers to a website called AskUrza.com, where you can select the loyalty ability you're using.

Each loyalty ability has 20 effects, which could also be determined with a twenty-sided die.

On this page you can see all possible effects and a Planeswalker which utilized a similar or identical effect before.

Whether fighting Phyrexians, founding the Tolarian Academy, or just enjoying retirement, Urza always kept his head.