A former West Ham and Everton defender during his days as a player, ex-Croatia international Slaven Bilic will need little in the way of an introduction to most Liverpool fans.
However, since leading the national team to two major tournaments and knocking England out of Euro 2008 at the qualification phase, Bilic has undergone something of a transformation.
Now manager of Besiktas, the 46-year-old, who was scary at the best of times, is sporting a Roy Keane-esque beard that is sure to have left plenty of opposing managers quaking in their boots upon meeting the near-6ft 3in Croatian icon.
With Liverpool due to face the Turkish side in the knockout phase of the Europa League, we've compiled a list of five of the most frightening images of the manager to date, so that Reds fans can be prepared for what comes next.
Even from the sanctity of the bench, Bilic is able to project fear onto the pitch, helped in no small part by staring forwards blankly while sporting a Khal Drogo from Game of Thrones-style beard, that oozes both intimidation and manliness.
Here we see the big Croatian channeling Joe Pesci's Tommy DeVito from Goodfellas during one Europa League clash with Tottenham. Cuddling opposite number Mauricio Pochettino in close, it's not clear whether he wants to kiss or kill the Spurs boss. We think maybe both.
You would think the presence of former Premier League hotshot Demba Ba at the Istanbul club would cheer Bilic up, but you would be wrong. The Senegalese striker may have scored 16 goals in 18 games for Besiktas but that doesn't prevent his manager from unleashing a a 1000-mile stare on reporters during press conferences!
Unsurprisingly, referees have come in for a fair amount of criticism from the ex-Hammers stopper over the years, with this shot demonstrating Bilic's potential as either a hypnotist or school teacher. On the basis of this picture, you wouldn't want to be late for class...
Not even World Cup legends are safe, with Bilic showing no hesitation in giving opposite number and super-bendy-free-kick supremo Roberto Carlos an earful during a heated Turkish Super Lig clash earlier this season - as if Brendan Rodgers didn't have enough to deal with already!