Just had an idea to deal with this, especially if the players have read the Monster Manual etc.
Create a home-brew dungeon that the players are going to explore. Let them, if they bother, find out a little of it's background, that it was constructed by a mad mage. Nothing new there right? Except the mage was actually an illusionist who's final insane masterpiece was to alter the appearance of all the creatures/monsters in the dungeon. Players see a troll but it's actually a Ogre Magi. Or a band of Kobolds but instead they're Phase Spiders and so on. This stop this out of character, metagaming crap immediately. It also brings back the suspense and trepidation that has been lost in most ttrpg's these days.
Just had an idea to deal with this, especially if the players have read the Monster Manual etc.
Create a home-brew dungeon that the players are going to explore. Let them, if they bother, find out a little of it's background, that it was constructed by a mad mage. Nothing new there right? Except the mage was actually an illusionist who's final insane masterpiece was to alter the appearance of all the creatures/monsters in the dungeon. Players see a troll but it's actually a Ogre Magi. Or a band of Kobolds but instead they're Phase Spiders and so on. This stop this out of character, metagaming crap immediately. It also brings back the suspense and trepidation that has been lost in most ttrpg's these days.
oh man.. that’s a GREAT IDEA.