Chaotic Form

You cause the form of a willing creature to become
malleable, dripping and flowing according to the target’s
will as if the creature were a vaguely humanoid-shaped
ooze. The creature is not affected by difficult terrain, it has
advantage on Dexterity (Acrobatics) checks made to escape
a grapple, and it suffers no penalties when squeezing
through spaces one size smaller than itself. The target’s
movement is halved while it is affected by chaotic form.

At Higher Levels. When you cast this spell using a spell
slot of 5th level or higher, the duration increases by 10
minutes for each slot level above 4th.