1 Kyros: Stand back! I’ll take care of this scorpion.
2 Mordekai: How come you always tell us to stand back and you’ll take care of it?
3 Mordekai: We’re experienced fighters. We know everything there is to know about hundreds of monsters! We can handle a hostile critter.
4 Kyros: You know they’re venomous?
4 Mordekai: All yours!!

It's an interesting question to consider in your standard fantasy roleplaying game: Exactly how much do adventurers know about the various monsters they may encounter?

Back in the early days of Dungeons & Dragons, it was encouraged and expected that beginning adventurers were in a strange and frightening world, and had no real idea what abilities, strengths, and weaknesses various monsters might have. The Dungeon Master was encouraged to describe monsters cryptically, so as to not give away what they were.

"You see a shuffling figure, about the size of a man, with a reddish face and blue nose, heavily muscled, with short, stiff bristles on its brown forearms. It wears a black leather jerkin over red clothing and raises a battleaxe as it spots you."

It was only after fighting several such monsters that you might learn that they were hobgoblins.

Over time, as players became more familiar with the game, it became more common for players to have read the various game rulebooks, and know exactly what a hobgoblin is, and also that it has 1+1 hit dice, armour class 5, and live in tribes that engage in mining. Within the game, experienced adventurers might also know this information.

In the modern day, it's become more common for players to have easy access to game rules information and lore. There's an argument to be made that within the game freshly minted heroes have more knowledge of their worlds these days too. The 5th Edition D&D rules encourage the idiom that beginning characters are already somewhat experienced, having had past professions and being generally more developed than the fresh-faced, naive teenagers seeking their fortune that was common with early editions of the game.