Overwatch has revealed via Twitter that the next hero, due in July, is indeed Hammond as the community suspected. The Horizon Lunar experiment, revealed to be a hamster with augmented intelligence, utilises a spherical mech with four extendable limbs and two gattling-gun arms to battle.

It seems he might be a new Tank hero, going off appearances (and the hamster ball like mech is pretty awesome in our opinion). Respawning will report on this situation as more information is revealed.