One of my BFFs told me she was doing some smocking on a dress for her granddaughter. When I told her that I had once taught smocking on the serger - she said "WHAT, HOW?"
This is done with a 5 thread serger - the triple cover stitch using the 3 front needles. Set up the serger for gathering (needle tensions may need to be adjusted to a higher number, lengthen the stitch and adjust the differential feed). The trick is place elastic thread in the looper. To prevent a lopsided look, you may want to go up one side and then reverse direction. You will need a lot of fabric because it does bunch up the fabric like smocking.
Testing on scrap fabric first is a MUST!
When I taught this class we made a book cover. For the crisscross stitch - we used the chainstitch.
You may not want to try smocking but give the elastic thread a try in the looper for a different effect. But please note - do not cut the thread too short - the elastic thread will snap back and the stitches will unravel. Tie the end threads in a knot to secure the stitch.