Arcane Bubble

cast the spell on any point you can see in range, creatures that you choose may enter and exit at will, hostile creatures when trying to enter or exit must do an arcane or con saving throw if failed creature rolls 1d20 to see what damage they take. once you roll the bubble will do an attack of that Kind. 

1 - 3 fire                      13 - 15 lightning

4 - 6 slashing             16 - 19 max falling

7 - 9 necromantic     20 fear of bubble

10 - 12 poison