This is definitely not the main point or even an important point, but:
If a giant spider jumps on your child
It is very unlikely that a giant spider will ever jump on your child. Any spider that is likely to jump on your child (or on anyone or anything) is overwhelmingly likely to be very small.
(Also, any spider than can jump on anything is almost always going to be completely harmless, but of course that generally doesn’t affect your visceral reactions.)
This is definitely not the main point or even an important point, but:
It is very unlikely that a giant spider will ever jump on your child. Any spider that is likely to jump on your child (or on anyone or anything) is overwhelmingly likely to be very small.
(Also, any spider than can jump on anything is almost always going to be completely harmless, but of course that generally doesn’t affect your visceral reactions.)