Roald Dahl did not fuck around. He grew up in one of those psychopathic early-20th-century British boarding schools, and then went to Africa once he graduated, and World War 2 broke out and he fought in Egypt and Greece.
He wrote children's literature because kids tend to vibe with how his brain works, but he was not playing games. Read his adult short stories sometime.
Edit: From his autobiography, from early on in his time in Africa:
Suddenly, the voice of a man yelling in Swahili exploded into the quiet of the evening ... He was yelling from somewhere behind the house. "Simba, bwana! Simba! Simba!"
Simba is Swahili for lion. All three of us leapt to our feet, and the next moment Mdisho came tearing round the corner of the house yelling at us in Swahili. "Come quick, bwana! Come quick! Come quick! A huge lion is eating the wife of the cook!"
That sounds pretty funny when you put it on paper back here in England, but to us, standing on a veranda in the middle of East Africa, it was not funny at all.
Robert Sanford flew into the house and came out again in five seconds flat holding a powerful rifle and ramming a cartridge into the breech. "Get those children indoors!" he shouted to his wife as he ran down off the veranda with me behind him.