The Overwatch Twitter has a warning for all players: "Beware of small mammals. Wrecking Ball rolls into the fight 07.24.18". That means, for those who do not read well between the lines, that Hammond, a.k.a. "Wrecking Ball", is coming to Overwatch on July 24th.
Hammond is a tank character, the game's seventh, and "provides disruption while also being an aggressive bruiser that bullies the enemy's back line, eliminating vulnerable heroes that are left unguarded". His specialty is disrupting enemy positioning by using the Roll and Piledriver abilities.
Wrecking Ball can confidently start team fights at any time by rolling into the enemy team and popping Adaptive Shield, which makes him incrementally more difficult to eliminate for each enemy nearby. If a fight is no longer going in his favor, Wrecking Ball can easily escape from the fray by using Grappling Claw to quickly swing back to the safety of his team. Minefield can prevent enemies from reaching a preferred location or can be dropped on top of them to cause an explosive burst of damage on all foes in a single location. He can also get the drop on his foes by using the Grappling Claw to swing over his enemies, showering Minefield on top of them, and then finishing with Piledriver to pull them into the mines for an explosive burst of damage.
You can check out Hammond's backstory and a bunch of screenshots on the Overwatch site.
If you'd like to try out the little guy ahead of next week's launch, he is live on the PTR.