Slave of Bolas — ruling 1

You may target a creature you already control.

Slave of Bolas — ruling 2

If you don’t control the targeted creature when the “at end of turn” ability resolves, it won’t be sacrificed. If it’s still on the battlefield but under another player’s control, the ability won’t try to have you sacrifice it again at the end of the turn after that.

Slave of Bolas : règles, fonctionnement et interactions (MTG)

Slave of Bolas is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Gain control of target creature. Untap that creature. It gains haste until end of turn. Sacrifice it at the beginning of the next end step.

How it works : Slave of Bolas

Original English text — Wizards of the Coast / Scryfall

#1May 1, 2009· Wizards of the Coast
You may target a creature you already control.
No other card is named in this ruling.
#2May 1, 2009· Wizards of the Coast
If you don’t control the targeted creature when the “at end of turn” ability resolves, it won’t be sacrificed. If it’s still on the battlefield but under another player’s control, the ability won’t try to have you sacrifice it again at the end of the turn after that.
No other card is named in this ruling.