So back to the lobster moth Caterpillar. (Stauropus fagi).
Remember, this is what it looked like...? but look at the other photos below on a different day and conditions.
In the first instar (our word for today… An instar is a developmental stage of arthropods, such as insects, between each moult, until they become adults/sexual maturity is reached) the caterpillar feeds entirely on its own egg-shell and is unusual in that it mimics an ant or small spider, with its long thoracic legs.
During the following instars (what does that mean again?) the caterpillar develops even more of an odd appearance with a distinctive round smooth head, whilst it retains its long thoracic legs which it often folds underneath itself. It also has raised humps on the fourth to seventh segments and a greatly swollen anal segment that has the claspers modified into long thin structures that look like antennae.
The colour is reddish brown, but they seem to change, as you can see from the photos as I went back twice to keep photographing before they disappeared. In its resting position its weird body shape seems to provide perfect cryptic camouflage, tho I managed to spot them as the plant they were feeding on was almost entirely eaten and they looked like burnt twigs, so I investigated.
These larvae can grow to a length of 70 mm and if disturbed by a potential predator - or photographer - can put on a menacing display with the thoracic legs splayed out and the head arched back over the body. After the moth pupates in a strong cocoon, the moths emerge the following year from May until July depending on conditions.