Sense of to exist, be present is attested from c.1300. Meaning to pay for as a treat is from 1821. Phrase stands to reason (1620) is from earlier stands (is constant) with reason. Phrase stand pat is originally from poker (1882); stand down in.
In Expert Mode, Wall of Flesh is seen to be significantly faster than his prior speed, posing map navigating harder as the players are demanded to plan out their routes fasters. In addition, getting pulled by his tongue will inflict additional damage to the player, possibly killing a weakened player.
Once the mouth dies, the entire body will begin moving faster and also be open to attack. Once the body is destroyed, the drops from the Wall of Steel will spawn inside a square of Demonite/Crimtan Bricks. After the defeat of the Wall of Steel, it will drop 4 Flags. Once you use one, a message will appear saying The ancient spirits of light and dark have come to wage war!. This marks the beginning of War Mode.