Magic Syphon - Spell level 5

As according to your pact, you gain one spell at random from the foe you've slain.

The spell has to be one you can cast and learn. It does not count against the amount of spells you know. Each spell can be used once a day, and will not use up a spell slot.

You can gain up to 3 spells this way. If you gain more, you have to choose whether or not to swap out one spell. This before the DM will tell you which spell you will gain.