There are times when supporters don't exactly get what they want in a transfer window, with their teams sometimes signing players they aren't particularly convinced by for one reason or another. And this usually leads to a few too many comments on social media.In the case of Dusan Vlahovic's potential move to Paris Saint-Germain, however, ultras have done more than just comment on Twitter. Instead, not doing things by halves, they have presented a banner threatening to cut off three of the striker's fingers if he makes the move.Something tells us that'll be enough of a warning for the Serbian, who may opt to stay among the chaos at Juventus with a perfectly intact hand, rather than likely silverware and three fewer fingers in the French capital.The question is, why have PSG ultras reacted to the rumours in such a way?