Contingency

Level: 6

Casting Time: 10 minutes

Range: Self

Duration: 10 days

Choose a spell of 5th level or lower that you can cast, that has a casting time of 1 action, and that can target you. You cast that spell--called the contingent spell--as part of casting  contingency, expending spell slots for both, but the contingent spell doesn't come into effect. Instead, it takes effect when a certain circumstance occurs. You describe that circumstance when you cast the two spells. For example, a  contingency  cast with  water breathing  might stipulate that  water breathing  comes into effect when you are engulfed in water or a similar liquid.

The contingent spell takes effect immediately after the circumstance is met for the first time, whether or not you want it to, and then  contingency  ends. The contingent spell takes effect only on you, even if it can normally target others. You can use only one  contingency  spell at a time.

If you cast this spell again, the effect of another  contingency  spell on you ends. Also,  contingency  ends on you if its material component is ever not on your person.

Source: PHB, page 227. Available in the SRD.