The "commander tax" increases based on how many times a commander was cast from the command zone, not how many times it was put there as a result of Commander rules. The returned commander will cost more to cast again even though it was put directly into the command zone.
23-08-2019
wotc
Leadership Vacuum targets the player, not their creatures. A commander with hexproof or protection from blue may be returned this way.
23-08-2019
wotc
You'll draw a card even if the target player controls no commanders as Leadership Vacuum resolves.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.