Time fray

You look ahead in time, and take a small thread of of knowledge. This is represented as a 3ft long silver string. At any point during the duration you can choose to apply advantage or disadvantage to yourself or a creature within 30ft  For an attack roll, saving throw or ability check. For every time you do this one foot of string disappears. When all of it is gone or at the end of the spell the string vanishes in a puff of smoke. 

At higher levels: you get one additional foot of string for each slot above 3rd.