What's your favourite piece of football memorabilia?
An autograph? Maybe a shirt worn by your favourite player?
How about the DNA of your club captain?
That is exactly what Swedish champions AIK are offering this Christmas.
For 3,499 Swedish krona (£307) fans can buy the crystallised DNA of club legend Nils-Eric Johansson, who was forced to retire in February because of a heart defect.
The 38-year-old's genetic make-up comes in a test tube and lasts for 500 years.
"It's like Jurassic Park!" Johansson tells BBC Sport. "In 500 years, you might see a lot of Johanssons running around, who knows?"
Johansson says technically he could be cloned, but a section of the DNA is removed to prevent "illicit or illegal behaviour".
"It is not 100% me; it is 99%. That 1% is very important for my own sake and protects my copyright to the DNA," says the former Bayern Munich, Blackburn and Leicester defender.
"You would not be able to put my DNA on a crime scene for instance, as it would not match perfectly, so you could tell it wasn't me."
He jokes: "[If you cloned me] it would probably be right-footed instead of left-footed."
How? Why? And other pertinent questions...
Johansson was introduced to the company DNAMQ, which "integrates identity into products" and was founded by former AIK, Chelsea and Coventry goalkeeper Magnus Hedman and Dr Robert Grass.
Former Sweden international Johansson went to the Swiss laboratory of Dr Grass, who took a swab from his mouth to be able to mass produce the DNA, which he says looks like "snow or ice".
Former Motorhead drummer Mikkey Dee has undergone the process, although it is thought that Johansson is the first sportsman to sell his DNA.
"You can get a worn match shirt that will have DNA in it, but it will be washed out," Johansson says. "This is a way to keep you crystallised for 500 years.
"You can bring your favourite player home with you, keep him and have them for a very long time. A lot of fans love to collect things - this could be one of those things.
"When I first got asked to do this, I was taken aback, I thought it was quite scary - has technology gone too far?
"But it is fun to push the boundaries, see if the fans like it, and the reaction has mostly been positive.
"My wife is OK with it. We have the ultimate DNA of our three kids running around at home."
AIK have produced 371 boxes, one for each game Johansson played for the club, containing a test tube of DNA, a captain's armband with his face printed on it and a certificate of authenticity.
Some of the proceeds will go to a charity in Sweden, and Johansson said it was "hard to put a price tag on DNA and myself".
"Each box represents one game I have played in. There a lot of stories in one box," he adds.
'I could have died on the pitch'
Johansson won the Bundesliga with Bayern in 2001 and the League Cup with Blackburn in 2002, having joined for £2.7m the previous year.
After two seasons at Leicester, he joined AIK in 2007, but in February this year was told by doctors that he could not play again because of a long-standing heart issue.
Johansson was born with the heart problem and has known about it since he was 20. However, aged 38, he was advised to retire two weeks before the season.
AIK paid tribute to Johansson by adding a picture of his face and the words "#4 - Our Captain" to the sleeves of their shirts for the season.
The team won the Allsvenskan in November and Johansson was invited to lift the trophy alongside captain Henok Goitom.
"It was a risk I was not willing to take. I am 38 and have got three kids. My career was almost done anyway," he said.
"But it was a lot to take. I had done pre-season and worked so hard to get in shape and compete with the youngsters, when the doctors said 'no more'.
"From then on I had to watch from the stands."
He added: "I am very lucky and happy they saw it. Had I continued, something might have happened and I could have died on the pitch.
"At the same time, I felt fit and thought 'why can't I play and do what I love?' It comes back to my family and making sure I am there for them.
"Sometimes I wake up and think I am going training. There is something strong inside me that's hard to change."