The players in my game recently came across a fairly powerful magic sword as the first magic item they found. Shortly after that, they wound up in a boss fight.
The players came up with the ingenious idea of having one player attack with the sword, then hand it to the a nearby player so they could attack with it too. At the time I ruled that passing an item to another player would take an action, so they couldn't do that.
But now I'm reviewing the rules and on pp. 190 of the PHB, it says handing an item to another character is "the sort of thing you can do in tandem with your movement and action." Does this mean it's possible for the PC's to surround an enemy and just pass the sword down the line (in initiative order) so that each one can attack with the same magic sword? That seems over-powered, and a kind of ridiculous way to narrate a combat.