Hey all. Checked the FAQ, did some searching, couldn't find the answer.

Infernal obsession. Say I've played it on some character. My opponent uses some ability to discard the attachment itself. Would the character revert back to the original controller's control?

I had always played that yes, the card would switch back. But now I'm not so sure. Some sections from the faq:

(v1.0) Duration of Effects
If a triggered ability has no specified duration, then the effects of that ability expire at the end of the current phase. “Put into play,” “Remove from play,” and “Take Control” effects are all an exceptions to this rule, and unless specified by a specific duration are considered to be permanent effects.

In fact, I've reread the whole section on the Duration of Effects and the section on Attachments a few times, and can't find anything that would mean it switches back to the original.

Now for the REALLY fun example that actually occurred today:

I took control of Paul Lemond. Later, my opponent used Repo Man to take control of the attachment. (We ruled that it makes Paul go back). So he played it on Paul so that he could legally play it. Later, I play a new copy of Obsession on that Paul. It took us awhile to figure out what happened, but i ended up with him, and he had 2 infernal obsessions on him. (I think we messed this up, since he should have lost the first obsession that was played on his own character) and that prevented him from re-repo manning it again since he already controlled it. My head hurts.

the card is pretty straight forward.

Hastur
•Infernal Obsession
-
Type : Support
Cost : 3
Subtype : Madness. Attachment.
Game Text: Attach to a non-Ancient One character. While attached, you gain control of attached character. (If control changes again, discard Infernal Obsession from play.)

if the attachment is discarded you no longer control the character. "While attached, you gain control of attached character"

Once he took back paul, the attachment should have been discard. "If control changes again, discard Infernal Obsession from play."

which then later you could have played the other obsession and took control again.

For your example with the Repoman you have to think about this point of the faq :
" If a card effect allows you to take control of a card, move that card into your playing area. If that card is an attachment, immediately attach it to an eligible card you control . (If you cannot, then you may not take control of the attachment.)"

So with the Repoman you gain control of Infernal (an attachment), you must move the Infernal on a character you control in your own play area (you gain control of a character you control already but it's not a problem). So, now Paul has no more Infernal on him, he returns in your play area.

With the Repoman you don't steal the attachment + the character, you steal only the attachment.

And yes you can't never have 2 Infernal on the same character because it is discarded if control changes (the same if you play a blind submission on an character with Infernal, the control changes in the same way, The Infernal is discarded)

Thanks all,

Somehow we both missed the "While attached" phrase in the text which makes the whole question 100% silly.