icky stuff (5)
I believe the answer is:
slime
'icky stuff' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for slime that I've seen before include "Goo" , "Sludge, gloop" , "Unpleasantly moist and slippery substance" , "Gunk" , "could make things sticky" .)