Drop shield

You create a soothing shield in a 10 foot radius sphere that
heals the wounds of allies within it's boundaries. The shield's
hit points are equal to (your caster level) x 5 and has an AC of
10. All creatures can enter and exit the shield freely.
Creatures friendly to you that start their turn within the
shield or enter it's area for the first time regain d4 + your
spellcasting ability modifier hit points. Attacks and spells
cannot be cast from within the shield at enemies outside of
the shield, or vice versa, but can target the shield itself. If the
shield's hit points are reduced to 0, spell ends.