If a spell is being casted within 120ft of you, you can absorb the spell. On your next turn, you can use your action and bonus action to re-use this spell or it is lost. 
For every spell cast there is a chance for failure. Cantrip - 3rd 20%, 4th 30%, 5th 40%, 6th 50%, 7th 60%, 8th 70%, and 9th 80%.