Legend cards are designed to combine, creating a larger, more powerful legendary Pokmon
If the original event is entirely replaced (such as by applying Soul-Scar Mages replacement effect), the original event wont happen
If you combine this with another card farther down on the list, you get to draw two cards for each casting
Mono artifacts were artifacts that would be tapped as a cost to activate their abilities, whereas poly artifacts could activate their ability as many times as a player could afford to do so
The cards don't have to be touching your head, so they can be balanced on top of a hat, for example, but you can't put something on top of them or use adhesives to keep them in place
Then you can -3 him to Vindicate something with colors or +1 him to exile our top card and then drop a 2/2 colorless Spirit and then when it dies you draw it