Crystal Strike

A huge group of crystals burst from the ground in a 15 ft. square area that you can see. The ground in which this spell is cast is considered difficult terrain. If there is a creature within that area, you can choose to attempt to trap them inside the crystals, and they must make a Dexterity Saving Throw against your Spellcasting DC. You can choose to make the crystals disappear at any time so long as you can still see them. If you do not choose to make them disappear, they will disappear on their own after 8 hours.