Last night I was playing a friend. I had Professor X mind control the Cable/Deadpool figure and used it to attack my opponents click. The cable/Deadpool at the time he was mind controlled had probability control. As I was using my opponents figure to attack something was I able to use the figure's prob control to retool my attack?

The mind controlled character is friendly to the mind controller, until the action is resolved, the PC is yours

Since he is friendly to you, you can use his PC on your attack. Also note a common misconception - PC is not a free action, it is not an action of ANY kind

Challenge someone - if they say it is a free action, offer a bet, loser eats the PAC, if they can find the word action in the power description

Yes, that is legal.

Thanks thats what I thought! Follow up question: since the PAC says once per turn for PC does this mean once I am done MCing that character can he then use PC on that same turn or is it used up?

Mind controling an opposing figure and using something that is only once per turn/round/game does not prevent the controller from doing those things during that turn/round/game.

If ur mindcontrolling his character its not his turn. You wont be abe to use any more on that turn(being ur turn that is). Once ur turn is over the use of PC is again available at the begining of ur opponents turn.

Ah I get it! So even though it was his figure it counts as my PC for the turn and not his. Thank you everybody!

Ok here's a follow up question, If I have multiple mind control figs and MC the same fig multiple times may I use PC each time it's MCed?

The reason for this is that with free actions they can be used per MC. I know PC is not a free action but since the fig goes back to being controlled by it's original controller would that also reset the PC use?

I will have to remember that. Thanks for good question.

That is a-ok.

Here's the important rules bits.

From the Player's Guide:

 When a character is affected by Mind Control, any of its powers
previously countered remain countered. Powers that may only be
used once per turn, round, or game may be used accordingly per
Mind Controller.

Probability Control:

Once during your turn, this character allows you to reroll one of
your rolls, ignoring the original roll. A character using this power
must be within 10 squares and line of fire to the character for
which the original roll was made. Using the same rules, once per
round during an opponent's turn, this character allows you to
force that opponent to reroll one of their rolls, ignoring the
original roll.