What happens to equipment attached to a creature that is returned to its owner's hand?

When a creature leaves the battlefield — including being returned to its owner's hand — any Equipment attached to it becomes unattached and stays on the battlefield as an artifact. Equipment cannot move to a player's hand along with the creature it was equipping. This is governed by CR 301.5d, which states that if an Equipment becomes unattached from a permanent, it remains on the battlefield unless another effect moves it.

The reason this happens is rooted in how Equipment works: it is a separate permanent from the creature it's attached to. When the creature changes zones (moving from the battlefield to the hand), the Equipment simply loses its attachment point. CR 704.5p reinforces that Equipment that is attached to an object that has left the battlefield becomes unattached as a state-based action.

Importantly, the Equipment does not go to the graveyard, does not return to the hand, and is not sacrificed — it just sits on the battlefield, unattached, and can be equipped to a new creature later by paying its equip cost.

Example: Your Grizzly Bears has a Greatsword attached to it. Your opponent casts Unsummon, returning Grizzly Bears to your hand. Greatsword stays on the battlefield, unattached. On your next turn, you can pay the equip cost to attach it to another creature.