Acid Sheath (3.5e Spell)

''This spell, designed as a protective measure, is often used by less scrupulous mages as a way to protect themselves. It coats the user in a sheath of acid which causes anything that touches them to burn and melt.''

Any creature striking you with its body or a hand-held weapon takes 1d6 acid damage + 1 acid damage per caster level. Creatures wielding weapons with exceptional reach are exempt from this damage.

Additionally, you gain acid resistance equal to your caster level or 5, whichever is better.