All is not what it may seem. The Ladybird hides a folded up pair of wings under its carapace and the slug actually has the vestige of a shell inside that splodgy body.--(believe me, I remember that much from my Zoology lectures 'way back in the early 60s!) Which brings me to the following anecdote.
My younger brother was a scrawny little under 10 year old and had been prancing about in front of the bedroom mirror without his shirt. He turned his head round to view the reflection of his back and dissolved into tears. On questioning him he announced to mother that he was growing wings; he was a freak! He would always have to wear a roomy shirt to allow for their growth.
What he had seen were his shoulder blades sticking out!