Aganazzar's Hurlgate

You create a darkly transparent orb of 10 foot radius at a point you can see within range. Any creature which encounters the area of the sphere is captured by it. A creature that is captured by the hurlgate begins floating within it as if there is no gravity there. This imposes disadvantage on melee weapon attacks, otherwise a creature inside can take actions as normal. Flying creatures may fly out of or through the hurlgate as if it was difficult terrain. A creature may use an action and 15 feet of movement to make a Athletics or Acrobatics check to escape the hurlgate.

When you cast this spell, and as an action while you are concentrating on it, you can move the hurlgate 30 feet, not necessarily in a straight line. Whenever the hurlgate moves, it brings all creatures with it who are captured by it. When the hurlgate has captured four creatures, or when you lose concentration, or at any point of your choosing, it immediately moves 60 feet directly upwards, unless blocked by a ceiling, and stays there until the start of your next turn, at which point the spell ends.

When you cast this spell using a spell slot of 7th level or higher, the hurlgate can capture one additional creature for each slot level above sixth.