Winter Cam-dle

Realizing that in order for Lightning McQueen to have cacti stuck to him that the paneling would have to be soft enough for cacti thorns to pierce.
Realizing that he doesn't need any visible repairs after this, meaning it healed on its own.
Realizing that for all of this to be true that they need to be made of either a living material similar to matoran or cybertronians or that their paneling would just plain feel like oiled skin to the touch.