There was a sense of desperation about Arsenal's transfer activity in January.

In a hectic few weeks, the Gunners bought Pierre-Emerick Aubameyang, Henrikh Mkhitaryan and negotiated a contract extension for Mesut Ozil.

That's not to mention the sales of Alexis Sanchez, Olivier Giroud and Theo Walcott.

Of all the deals, however, it was probably the signing of Aubameyang that had Gooners the most excited.

The Gabon international had gained a reputation as a prolific goalscorer during his time with Saint-Etienne and Borussia Dortmund with Arsenal eventually forking out £56 million for his services.

Aubameyang signed for Arsenal in January

Nevertheless, there were a few question marks over the deal, even if Aubameyang has gone onto prove himself as an accomplished scorer in the Premier League.

Sky Sports pundit Gary Neville noted at the time: "If the top clubs wanted him, the Real Madrids, the Barcelonas, Jurgen Klopp needing back-up for Firmino if he gets injured, Arsenal had a free run at him.

"There was never a mention of any other clubs coming for Aubameyang, so my nervousness is because no one else came in for him."

Aubameyang's crazy contract details

And not only did Arsenal have a free-run at Aubameyang, but details revealed on Friday by Football Leaks shows they went to some pretty astonishing lengths to sign him.

In fact, some of the clauses are pretty mental.

Aubameyang's deal gave him a £198,000-a-week salary but - rather incredibly - also an eye-watering £18.2 million signing on fee. Yes, you read that right... £18.2 million.

For a little bit of context, that's almost thrice the signing on fee given to Sanchez in his United.

That's not all, though, with Arsenal paying Aubameyang a hefty £250,000 for every game Arsenal win with him starting.

He could have the game from hell, get sent off and contribute nothing but if Arsenal win, he would still pocket the top prize of Deal or No Deal.

And the most remarkable clause of all, regards a £2.26 million 'Champions League' bonus that Arsenal have paid out despite not even qualifying.

Shady to say the very least.

Not only do the numbers reveal Arsenal's desperation to sign him in the first place but, seemingly, to hold onto him with the inexplicable payment of the Champions League bonus.

As success as the club's January transfer window appears to be, it's clear Arsenal went to some rather uncharacteristic lengths to ensure it.

It's a good job he's already scored nine goals, hey?

Do you think signing Aubameyang was worth all the effort? Have your say in the comments section below.