Using Gangplank'sParrrley with Tiamat will give you extra gold for every single minion killed with Tiamat's passive effect.
In Babylonian mythology, Tiamat was the first dragon and was slain to make the heavens, earth, and man.
In the V18.104.22.168 April Fools day patch Tiamat was renamed to Tamat, the name of a Rioter.
Tiamat is also the name of the five headed dragon goddess in the Dungeons And Dragons RPG.
This item is very similar to the DotA item Battlefury: Both requires 2 attack damage items and 2 regeneration items to build (althrough Battlefury have mana regeneration rather than a second health regeneration) and both gives area of effect damage on autoattack for melee only.