Hostile Takeover
Card Text & Abilities
[Hidden] (Hide now for [A] to react with later for [0].) Take control of an enemy unit at a battlefield. Ready it. (Start a combat if other enemies are there. Otherwise, conquer.) Lose control of that unit and recall it at end of turn. (Send it to base. This isn't a move.)
Official Rules FAQ & Clarifications
2 Official FAQsThere’s a gap in the current rules that leaves this situation without an obvious outcome. We plan to address that gap in the next regular rules update. The issue is surprisingly complex, and we’re not 100% sure what the answer will be when we’re done.
In the meantime, though, we believe starting a noncombat showdown is the least disruptive way to handle this scenario. If you need really precise timing: assume that your opponent loses control of the battlefield in the same cleanup that begins the showdown, even though ordinarily control is “frozen” once the battlefield becomes contested.
Temporal Portal
Units cannot be played to a base of a player other than their own controller under any circumstances. Because the owner of the unit is the one being instructed to play the unit, and the location they are being instructed to play it to is a base other than their own, it isn’t possible to play the unit. During the check legality step of finalization, the unit will be returned to banishment from the chain and all actions taken will be undone.