Puff Stitch

Intermediate Textured

Several loops pulled up to the same height in one stitch, then drawn together into a rounded, pillowy puff.

Work to the stitch where the pattern calls for a puff.
Yarn over, insert your hook into the stitch, and draw up a loop that's a bit taller than usual — leave it long rather than snug.
Repeat the previous step in the same stitch 3-4 more times without closing anything, so you build up several tall loops plus the original working loop on your hook.
Yarn over and draw through all the loops on your hook at once, then chain 1 to close and anchor the puff.

Unlike bobble stitch, a puff is built from drawn-up loops rather than unfinished double crochets, which is what gives it a rounder, softer profile instead of bobble's more angular bumps.
Keeping the drawn-up loops even in height is the main skill in puff stitch — uneven loops make for a lopsided puff.
Puff stitch rows are noticeably stretchier and squishier than the surrounding single or double crochet, which is part of why they show up so often in baby blankets.