Notes: I am the DM, my players are a group of 7, levels of 11 or 12.
So, our last weeks session ended with a black dragon releasing an acid breath attack on the only visible enemies in a courtyard. This was a servant, my wife's ranger PC, and her falcon animal companion. The servant and the falcon failed their Dex saves and took 58 points of acid damage, outright insta-killing both of them.
Going back to look at it as I prep for the upcoming session, I realize the falcon stats were incorrect. It should have 4 times the ranger's level in hit points. As she is level 11, this would mean the falcon should have 44 hit points. Not only that, but the falcon should have had the ranger's proficiency added to the Dex save, which would have made them pass the DC 18 Dex save, reducing the damage to 29 instead of 58.
As this was the last thing to happen at the end of last session, I wasn’t sure if I should retcon the hawk to still being alive and conscious, or leave it a pile of goopy acid and note that I will fix it with the next animal companion? What are my options in a situation like this and what are the pros and cons of making those choices?
Best Answer
Ask the player.
First there is nothing wrong with making a mistake, we all do it, you will make more, don't try and hide it. You're the DM you are tracking a lot of stuff mishaps happen.
Just ask that player what they want to do, do it before the session even starts. Pull them aside, explain what happened, (they should be tracking the companions saves and hp anyway, not you) and see what they want to do. They may be satisfied with their companion's glorious death, or they may feel cheated. Find out.
If they want the animal back tell everyone what happened, just like you did for us with what you forgot to do, (that takes care of any sign of favoritism) and then bring it back. If they want to try a different companion, let the results stand, and let them seek a different animal.
Fun is more important than a seamless narrative, if you make a mistake that impacts a players fun, fix it as best you can. If you make a mistake that does not impact anyone's fun, just make a note and try better next time. Heck sometimes a mistake is the best thing that can happen to your story, it's rare but sometimes a mistake can make the game more fun.