Fun facts.

Thomassuex

Tooth and nail restrain one's activities in line with present circumstances the full expression is to trim one's sails before the wind, but the shorter to trim one's sails is now more commonly heard. The term is obviously nautical, referring to sailing ships and alludes to the setting of the sails according to the strength of the wind. Sails would be reefed when the wind was strong and let out in gentler conditions. In the same way, someone who metaphorically trims his sails restricts his activities or expectations according to prevailing circumstances.
Ships that pass in the night see bolt from the blue.
Hoist by one's own petard variously and persistently troublesome or evil the hydra was an enormous nine-headed serpent in greek mythology. It lived in a marsh in the peloponnese, ravaging herds and crops and killing people with the poison of its breath. One of the 12 labours of hercules was to destroy it; when hercules attempted to do so he found that if he cut off one head two grew in its place, but he finally succeeded with the help of red-hot brands. In modern imagery, the hydra is used of any multi-faceted problem or wickedness that presents fresh difficulties as soon as one is solved.
Possums have one of the shortest pregnancies at 16 days. The shortest human pregnancy to produce a healthy baby was 22 weeks, 6 days — the baby was the length of a ballpoint pen.
Fall foul of come into conflict with from nautical jargon, in which the adjective foul has various meanings indicative of something wrong or difficult and the whole expression means 'collide with'.