Bubble

You create a 10ft sphere around you that has 50 hit points and +2 to your AC when it is broken anyone in a 10ft radius makes a con save or take 4d10 bludgining. you can breathe underwater and have a fly speed of 40 ft the bubble is resistant to one element of your choice and running into someone with it makes them make a Dex saving throw or they take 3d8 bludgeoning damage. For each level above 4th it has 10 more hit points