A: No. No matter how this plays out, you don’t get to keep Don’t Do That. Let’s run through some scenarios. We’ll call you Player B, and your opponent Player A (since it’s their turn).

Player A plays Can I Use That (CIUT).
They pull Don’t Do That (DDT) from the hand of Player B.

Player A must now play DDT as if they’d had it in their hand themselves.
Since there’s nothing which DDT can affect when it’s played during your own turn (unless some future susceptible card is created) DDT simply joins the used-up CIUT in the discard pile without having had an effect.

This is a pretty disappointing pull for Player A, but, on the other hand, Player B definitely does not get to claim Don’t Do That would act as though they had decided to play it, to prevent its own theft. Not only did Player B not decide to do that in a timely enough manner, it simply cannot protect itself once it is the target in question.

Don’t Do That can result in some pretty exciting plays… if you decide to use it. This is what Andy calls “The Curse of the Surprise” (after Surprises in Fluxx, which are similar to Don’t Do That). They have the potential to be so powerful that they become precious, and people hold back from using them… but, of course, they have no power at all if you don’t use them.

But could Don’t Do That have done anything, here? Well, yes, and no:

So, to lay out some of the more exciting ways this could have played out:

Player A plays Can I Use That (CIUT)

Player B plays Don’t Do That (DDT)
– they can decide to do this immediately after CIUT has been played
– they can decide to do this after Player A has declared they will target Player B’s hand
– they can even decide to do this after Player A has pulled a card to use…
…as long as the card pulled is not DDT itself. At that point, it’s just too late, as DDT can’t protect itself.

In any case, if Player B had successfully decided to use DDT themselves, CIUT is now in the discard pile, having been canceled, and DDT has been used up, and is also now in the discard pile.

Was it worth it? Player A’s turn (and card) have been squandered, and, although Player B has lost DDT, they’ve saved some other card in their hand from being taken and used by Player A. After all, that’s just the way DDT works: you have to use it up to get its benefit.

Ironically, we have seen that this is exactly what happens if DDT is the card chosen. Either DDT is randomly chosen instead of some more valuable card, or it’s voluntarily sacrificed to prevent some other more valuable card from being picked.

So, even if we had ruled that Player B was allowed to use DDT after it had been selected by Player A… it still wouldn’t result in Player B getting to keep DDT. Either Player B successfully used DDT to stop the play, in which case it’s used up and discarded, or they didn’t successfully use it, and it gets picked by Player A.

It’s just way more exciting for someone to make a conscious decision to disrupt someone else’s play, rather than wait and have DDT accidentally chosen. And, really – if you have a more valuable card in your hand, do you want to risk having it taken, or throw DDT under the bus on purpose to save the other card?

Of course then you run the risk of broadcasting to the rest of the players that you have a valuable card in your hand… OR, to double-overthink it even further, you make everyone think you have something valuable in your hand.