These Make Ready scrap sheets are just going to be thrown away, so they can be anything, even stuff leftover from the previous print run, the last time they had to calibrate the press
Team them up for an Xyz Summon and you can search your Deck for Melffy cards, lock attackers in place, or unleash the mother of all Melffy to turn your opponents monsters against them
There was also a short-lived inverse of Scry in the Time Spiral block, named Fateseal, which let a player use Scry on the opponent's library instead
Milling had definitely been established as part of artifacts' slice of the color pie (more on this in a bit), so Mirrodin was an excellent block to put more milling artifacts in
2021-03-19 Teferi's last ability means that in order for an opponent to cast a spell, it must be that opponent's turn, during a main phase, and the stack must be empty
On opponents turn we ready our quest, then complete it with the open mana