The lime green piping of Wales' grey away kit bears more than a passing resemblance to kryptonite - and the shirt seems to have as detrimental an effect on Chris Coleman's side as the fictional substance does on Superman.
Wales have lost all three of the games they have played in their current second strip of grey and charcoal hoops with a green detail - including both of their defeats in Euro 2016.
And although it may seem unlikely that a group of professional footballers would allow themselves to be unnerved by such a quirk, Wales do appear to be spooked by their unlucky away kit.
The Euro semi-finalists might have to don the unwanted shirt again on Thursday for their World Cup qualifier away against Austria, whose red home strip clashes with Wales' usual colour.
"I am not sure if they [Austria] will play in red or white, but I can tell you no-one wants to wear our grey kit. I will be happy if I never see that kit again," says Coleman.
"The red kit is the kit that we will always want to play in, we love being in the red.
"In years gone by I would have said to you that players do not care what kit they wear, but they do."
Coleman smiles at this point, but his admission is a startling one.
Welsh football is at an all-time high following the national team's run to a first major tournament semi-final in France earlier this year.
Yet there is a brittle apprehension among the players about swapping their familiar red shirts for the unlucky grey.
Wales lost their first game in the shirt - a 1-0 friendly defeat in Ukraine in March - and they were beaten by England when they wore it for the first time at Euro 2016.
Russia allowed them to wear red for their pivotal final group game, which Wales won handsomely, and they stayed in their home kit for the knockout victories over Northern Ireland and Belgium.
However, semi-final opponents Portugal decided Coleman's men would wear grey for their encounter - and the curse struck again.
"Portugal made us wear the away kit in the semi-final in the Euros, even though they were in their own away kit," Coleman adds.
"Russia thankfully allowed us to wear red when we beat them, but they could have made us wear grey."
With Wales likely to wear grey again in Austria, the game in Vienna could provide the chance to end their away kit hoodoo.
It may seem a trivial matter, but Coleman thinks Austria might try to exploit a potential Welsh weakness.
"If you are Austrian it is something you would look at, if you know the opposition prefer playing in a certain colour," he says.
"The players will talk about it, the Austrians will know about it, they should know about it.
"If we have to wear it we have to deal with it, but ideally we will be in red."