Maybe it's the left-footedness. The clinical finishing ability. The ghosting into space.
Arsenal have had forwards like Lucas Perez before but, just as Eduardo da Silva was taken from the club too soon, so too has 29-year-old Spaniard.
£4 million was all it took for him to join Jack Wilshere at West Ham, a fellow Gunners cast-off looking to rehabilitate his career.
Unlike Wilshere, however, he has performed consistently whenever he was selected by Arsene Wenger.
A talisman in Galicia
A talisman at Deportivo, Perez joined Arsenal on the back of a tremendous season in La Liga. In a struggling side, he'd scored 19 goals.
When the transfer was made public, Wenger purred to the assembled media;
"He's not only a goalscorer, he's a guy who combines well with partners, who can give a final ball and makes good runs. He's got a good eye for goal and had and outstanding season last year."
Reuters/Paul ChildsIt's baffling then, why the Frenchman used him so sparingly in the campaign that followed. He made just 21 appearances, starting only twice in the Premier League even as his competitors registered indifferent, asinine performances.
It didn't matter, seemingly, that Perez contributed six goals and five assists in his first 12 appearances. It didn't matter, either, about the clinician's precision of his hat-trick against Basel in the Champions League.
Maddening lack of appreciation
If Wenger's maddening lack of appreciation wasn't clear enough, it was hammered home by the signing of Alexandre Lacazette last summer.
The Lyon man requested Perez's number nine shirt with his compatriot only too happy to swipe it.
REUTERS/Fabian Bimmer"I couldn't give him the games he wants and deserves... I feel sorry for him on that front," Wenger admitted to reporters last season, before dispatching the unhappy player back to A Coruna on loan.
Perez went home, inevitably becoming top scorer. Deportivo had only got worse in his absence, however, and he struggled to impress in a team that was relegated despite the gesticulations of manager Clarence Seedorf on the sidelines.
Red Dead Redemption
With Unai Emery replacing Wenger this summer, some Arsenal fans may have hoped for redemption for Lucas at London Colney. There was room for him in his countryman's intensive 4-3-3, either as a central-striker or an inside forward.
The writing was on the wall, however, for a player that made just four appearances in a red shirt after Christmas 2016.
Casual observers will call Lucas a flop but others will be waiting for him to show his true worth at the Olympic Stadium. At a club that will finally give him the time and games he deserves, he might prove all of his doubters wrong.