Rarement will counter all magic with the highest level of the same spell you cast at it (counters flara with flarus, for example); if you doublecast, the spell it counters with corresponds to the first spell you cast at it, and does not counter the second spell. If you have Element Eater active, you can use this as a method of healing yourself and damaging the rarement at the same time For example; Kaim has "Fire eater" active, and casts Flarus at Rarement, Rarement takes 2300 damage, and Kaim is healed for 2300 when Rarement returns the spell.