The stonefish looks like a stone,just like the reef that it lives on it also likes to sit on the sandy seabed lt has spines, though,that it uses to defend itself they are very sharp and contain a nasty venom which can ba very painful and sometimes lethal to avoid the stonefish's nasty sting,you mustn't touch the reef while swimming and you should make sure you always wear shoes or sandals when walking in shallow,,sandy water