Excellent trick to be done with the proper audience.
I like to present it as an accidental transpo with a condom.
1. A card is chosen and disappears from the deck.
2. The magi announces it will reappear in the card box
3. When he opens the card box, a condom appears instead
4. The magi looks surprised, but explains it's probably due to a transpo between the card and condom.
5. He then changes the card into a wrapped condom that he gives to spectator to be opened.

This gives a good justification, IMHO, to the bizarre and sudden transformation of the card into the wrapped condom.

Nota Bene : I found that the condom is hard to unwrap in the end, because the condom enveloppe is very hard to tear.
This is a good point as it builds the suspense.
But that said, it might be a good idea for the magi to make a slight slit at the side of the wrapping before the trick, to facilitate the tearing.
Or to hold a tiny pair of scissors during performance, just in case nobody can tear the condom enveloppe.

This is an awesome mind blowing effect. Fun to perform.
The reason I gave this 4 stars instead of 5 is because the cards inside are like a fake Bicycle card. And more to that point, they're purple, not blue like the gimmick. If they were made with a real (and same coloured) card, this would be worth 5 stars 😊