Generally purple in color with a translucent quality that seems to make them glow.
Shaped like a vase, with many pits and grooves on the outside, they grow to be as much as 18" tall.
This animal.... yup I said animal. Is an aggregation of cells without any backbone (that makes it an invertebrate) or organs, that feeds by filtering water thru their bodies and eating the particles suspended in that water.
Predators do not eat them because they lack nutrition.... and their bodies contain glass like shards (called spicules) that make them pretty unpalatable.
I have gotten in the habit of looking down into each sponge, as I swim by.... 9 times out of 10 there is nothing to see.
But every once in a while, you get a surprise.... in this case a Hermit Crab.







