This warhammer is quite obviously made for a giant, although you have a suspicion they would call this a light hammer. The head of it is over 2 feet long and of substantial thickness. When stood on its head the iron knob at the end of its blue handle comes up to the shoulders of an average human. Judging by the crude markings and runes that could represent wind and sky chiseled into its face you can assume it’s the hammer of either a storm or cloud giant.
For its massive size it swings through the air with surprising ease, likely some form of magic to make it a more effective throwing hammer for someone of the intended size. It feels as if it weighs about 24 pounds although without the magic it probably weighs far more.
This hammer has the properties Heavy, Reach, and Two-handed. All creatures of size Large or Medium have disadvantage on their attack rolls with this hammer, and Small or smaller creatures can’t attack with it at all. On a hit this hammer does 3d8 bludgeoning damage, and on a critical hit it you can roll the damage dice three times instead of twice.
Hidden Property. If the magic on the hammer is dispelled or it enters the area of an anti-magic field the hammer instantly becomes 160 pounds and completely un-wieldable by a creature smaller than Huge until the magic is restored or it is removed from the anti-magic field.