Clockwerk + Spectre

Why this works

Catching a lone hero with Hookshot and Power Cogs gives Spectre the perfect setup. When Clockwerk traps a target, Spectre can use Haunt to instantly create an illusion inside the cogs with them. Since the enemy is isolated, Spectre's Desolate is guaranteed to do its bonus damage. The combination of Clockwerk's Battery Assault, the victim being trapped, and the extra damage from the Haunt illusion is usually enough to delete a support or even a core before they can react. It's a very reliable way to secure a kill.

This duo provides global pickoff pressure as soon as Spectre gets her ultimate. Clockwerk can be scouting or looking for an initiation, and Spectre can join the fight from anywhere on the map to secure the kill. This forces the enemy team to group up much earlier than they'd want to, which restricts their ability to farm safely across the map. Their main counterplay is to stay together as a unit to ensure any fight is a fair one, and to purchase items like Force Staff to escape the Cogs. This constant pressure often creates the space Spectre needs to farm her key items and become a late-game monster.