You briefly become ethereal and can move up to your speed as part of casting this spell. You can move through other creatures at no penalty unless they also exist on the ethereal plane. Moving through objects counts as difficult terrain. For each creature whose space you move through, you can have them make an Intelligence saving throw or be incapacitated until the end of your next turn. If you are underwater when you cast this spell, you may move up to double your speed and creatures who fail their save are stunned instead.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, your speed increases by 10 feet for each slot level above 3rd.