Dumb, Small, and somewhat easy.
these would occcur on the surface of water, if a kelp stalk was a part of a surface water block for a long enough period of time. kelp wads start as 1x1, and can grow to be 3x3 centered around the stalk. these can be walked on as a form of bigger lily pad, or harvested for a good bit of kelp.
Like i said: Dumb, Small, somewhat "easy".