Throws into the mix (4)
I believe the answer is:
adds
'throws into the mix' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for adds that I've seen before include "Does summer job" , "Goes on to say" , "Aggregates or makes further remark" , "Calculates the sum" , "Sums, totals" .)