Monsters with class levels?

[Hooligan]

I'd love to hear about your experiences with encounters in which the PC's opponents have been given class levels. Particularly with respect to expected & perceived encounter difficulty

A fellow DM was recently lamenting the apparent ease with which his party of 11th level pcs dealt with his "boss encounters".

His proposed solution? Give his monsters class levels from the PHB. Not humanoids, which often require class levels to remain challenging, but rather things like beholders, dragons, fiends, etc.

My gut reaction was that this would result in encounters of wildly unpredictable difficulty, even near-impossible ones depending on the particular monster/class combination. While I know the DMG has a section which describes how to make such "monstrous PC's, I have no personal experience as either a player or a DM dealing with/deploying such baddies.

[BillyBobShorton]

As a DM, I do it all the time. Not necessarily as "level x pc's" but more Like a band of orcs would have level 3 Champion abilities, and the leader might be a level 5 Eldritch Knight or Barbarian. One particularly pesky Goblin might have Ledgermain and a few spells w/sneak attack. Guards may get a couple Battle Maneuvers. Kobolds or lizardfolk types usually have one "shaman" with just enough annoying basic spells to make things more interesting. That kind of thing. Adds a lot to combat and lets players know they also have to occasionally watch out for class abilities. Table turns a little when you never know if a Light Cleric is lurking amongst some Hobgoblins or Bugbears.

The players seem to enjoy the variety over "pile of HP #1,2, & 3 all walk over and swing. Two miss. I hits. 7 damage. Ok players' turns. Orcs die."

Also giving one or two random enemies in a horde a weird tendency, like fond of shoving or grappling or really hates halflings, or something like that is another method to mix in and liven up "normal" encounters.

[Hooligan]

I should have specified that I don't mean humanoid opponents (which really need class levels to stay competitive), rather aberrations, dragons, fiends, powerful undead, giants, etc. Monsters that are already fearsome opponents.

[BillyBobShorton]

Gotchya. I don't usually add class abilities to monsters, I just kinda jack them up. Well... dragona get spells sometimes if you wanna count that.

[mephnick]

Just take a statblock you like, add a couple class abilities and then recalculate the CR. Definitely don't build using actual "class levels", that's just a waste of time.

If I were a betting man, your friend probably doesn't run a robust enough adventuring day and that's why his boss encounters fall flat. A party at full resources can easily beat a 5x deadly encounter without anyone dropping if they're remotely skilled at the game. A level 11 party at full resources can kill almost anything in the monster manual. If you don't wear them down before the boss fight don't even bother running it.

[Darth Ultron]

I do this all the time, and have for years. It works out great.

I give the more melee monsters a couple levels in melee type classes.

Fighter has action surge and second wind can give a good boost to most monsters. And Barbarians get rage.

Spellcasters are nice, though I fluff it more to 'instinct magic" and give them only self only spells. Spells like false life, jump, feather fall, mage armor, or haste.

Even just a couple levels can make fights much more of a challenge.