I’m using US terms.

what you can do with it:

The pineapple stitch is a decorative stitch that should only be made on the right side of your work, since the wrong side is not very pretty.  This is also a finnicky stitch so you may want to make a practice swatch before attempting to put it into a pattern.  It was also very hard to photograph because there were so many loops on the hook, so I’m afraid I only have written instructions.

how to do it:

The pineapple stitch is worked into a background of sc, and since you will be working into stitches 2 rows below to do the pineapple, you’ll need at least 3 rows of sc before the actual pineapples start.  If you want to do a sample as pictured above, with 3 sc in between each pineapple, ch 15 and work 3 rows of plain sc, counting your turning chains as a stitch.  On the fourth row, count your turning chain as a stitch as usual and work 2 sc in the next 2 stitches.  The next stitch is where we’ll put the pineapple.

For the pineapple stitch, insert hook like you’d make a regular sc, yo, pull up the loop.  (yo, insert hook into the stitch two rows below, yo, pull the loop up, yo, pull through two loops on the hook) 6 times.  Don’t pull the yarn too tightly when working in the rows below.  You should have 8 loops on your hook at this point.  Yo, pull through all 8 loops.  Ta-da!  You’ve done a pineapple stitch!

Sc 3, make another pineapple stitch, sc 3, make another pineapple stitch, sc 3.  You should be at the end of your row.  I did two more rows of regular sc before finishing the swatch above.