Mirror Move

You have been granted the ability to reflect others power back onto themselves, simultaneously granting your patron a glimpse of their next potential meal, gaining the following benefits:

• When a creature within 30ft. of you uses a combat feature (including taking an action that benefits from a melee ability, or gaining any bonus to AC, attack rolls, saving throws from a melee ability) you may take a reaction to make a Insight (DC = 10 + the creatures strength or dexterity score) On a success you gain those benefits or the ability to mimic that ability until the end of your next turn. 
• When a creature casts a spell within 30ft. of you that is a spell level equal to or less than your warlock level you may take a reaction to make an ability check with your spell casting modifier (DC = the original casters spell DC) On a success you immediately cast that spell at the same spell level as the original spell was cast, but you are able to choose new targets.

You may use this ability a number of times equal to your proficiency bonus per day.