Wild Magic Fog

A 20-foot-radius sphere of dense fog centered on a point within range blooms into existence. The sphere spreads around corners, and its area is heavily obscured.

This fog is thick and teeming with wild magic. Whenever a creature casts a 1st level spell or higher within the fog, they immediately surge on the wild magic island table, triggering the table's island effects. 

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the radius of the fog increases by 20 feet for each slot level above 3rd.