Alumin Adept's Rope Tangle

You touch a rope. One end of it hovers upward until the rope hangs perpendicular to the ground or the rope reaches a ceiling. Upon reaching the ceiling, the remaining rope tangles into an unwieldy knot that whips around rapidly. At the rope’s upper end, an Invisible 3-foot-by-5-foot portal opens to an extradimensional space that lasts until the spell ends. That space can be reached by climbing the rope, which requires a DC 15 athletics check to climb the length of it or take 1d6 bludgeoning and be knocked prone, after which the rope can be pulled into the space above.

The space can hold up to 3 Medium or smaller creatures. Attacks, spells, and other effects can’t pass into or out of the space, but creatures inside it can see through the portal. Anything inside the space drops out when the spell ends.