Time Dilation

You warp the passage of time by a factor of 10 in a 10 feet radius sphere centered on you. So inside the sphere time either passes 10 times quicker or 10 times slower compared to the outside. You choose.

The spell lasts for up to 10 hours in the outside world if you speed up the passage of time (so inside the sphere only 1 hour passes) or for up to 1 hour (10 hours inside). The Caster needs to continuously concentrate on the spell and thus cannot get the benefit of a long rest by using this spell. However your allies might be able to :)

The effect is stationary and does not move with the caster. Also the caster cannot leave the sphere while maintaining concentration on it. Other creatures can move freely in and out of the sphere.