Then, your opponent gets to do the same
If Imposter Mech enters the battlefield as a copy of a creature that was also a planeswalker, it loses both the planeswalker and creature card types
If Vorinclex leaves the battlefield after its second ability has triggered, that ability still resolves and the affected land won't untap during its controller's next untap step
Illustrated by Kekai Kotaki Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Not Legal Modern Not Legal Brawl Not Legal Legacy Legal Comp
It can either speed up or slow down anything with time counters, and being an instant means you can do it at the most disruptive moment
Within that deck, you get a copy of the rules, a paper playmat, handy damage counters, a tracker token, and a booster pack with 12 more random cards