Traps on the Fly in 5E

So a few month ago I talked about making a better trap and ideas for making more engaging and interesting traps, but sometimes you just want something that hurts or that can be whipped easy while improving.  At the same time one thing I hate about D&D (at least as it stands RAW) traps don't actually generate XP for overcoming.  Now again as I said in my other article it isn't that hard to put an XP value to a trap especially if it is one you take the time to plan out and put effort in, but an on the fly trap can be a bit trickier to know if you're giving too much or too  little. Luckily I think I came up with a simple solution to all of that.
Now none of these are complex puzzles or a one off "pop" type trap.  Instead I went the route of looking at a trap the same as a monster.  This means a few things, it is going to have a turn in initiative and it will be able to target enemies.  On the simplest level this is something like an arcane turret, but can also be more interesting things like an animated saw blade that has a network of rails to go almost anywhere in the room.

With this in mind a few things become much easier (such as figuring out XP), but what about disabling it with thieves tools? If I just ran it like any other monster and tools didn't work it wouldn't be special and honestly is WOULD just be a monster that happens to be a construct that can't move.  The fix is actually pretty easy though and something that makes those able to use thieves tool and especially rogues which can use their tools as a bonus action (and thus use them twice a round) and that's to let thieves tools check count as damage against a Trap Type enemy.  If the final "blow" is made with tools it is considered disabled and a GM might allow a DC check to reactivate it later (With the damage before the final blow being it's health.) On the same note as a GM I would probably allow a given amount of time (Probably an hour) and a tools check to regain "health" lost by the trap before reactivating it.  All that is GM digression but worth noting regardless.

So with the special mechanics out of the way you COULD just make a custom monster as a trap and be done, but doing that takes time and this is supposed to be for quick improve when players catch you off guard so now for some tables and pre-made templates.

Step 1:
First Select the Difficulty of the trap.  Personally I made four of them. One of each tier of play similar to the "Damage Level by Severity" table provided in the DMG.

Step 2:
So now you have the Attack bonus (or save DC), Health (Also combined tools DC to disable), AC, and XP reward, but  there's no flavor. What type if damage the trap does can say a lot about a trap.  The next table can be rolled on completely at random or you could roll a d4 for the top half for exclusively magical traps and the bottom half for weapon based traps. I know this includes thunder as a "Weapon", but in 5e that is sonic damage and a loud enough noise can me made without magic. If an roll doesn't feel like a good fit do remember that it's your trap and you can always jsut reroll and pick what you want.

Step 3:
The last step is deciding how the trap attacks.  At this point you might already have an idea and if that's the case go with it, but if not this table will let you know if it attacks a single target and or does area damage (Yes area could technically up the damage output per round, but that's only if your heroes don't think to spread out and that's their problem.

And there you have it.  What's the attacks range? Up to you.  Can it move around? Again figure it based on HOW it attacks.  Also don't forget the other nice part of making a trap an enemy is you can mix and match it with monsters when building encounters for added fun.

Side Note:
So I almost forgot, but a key factor in a trap is that it starts hidden. Now as a monster it would probably roll stealth, but again I think this is a time when traps being special should come in.  I would just have a normal Spot DC (Easy 10, Moderate 15, Hard 20, ect) to notice the trap against passive Perception unless they are specifically looking for traps.  If they don't spot it the trap gets a surprise round either with advantage to its attack or the target (or targets) get disadvantage to their save that round.

Also with the traps having a CR you could theoretically look at monsters of that CR and add or trade out attacks from the standard damage.  Examples would be the Magma Mephits explosive death for CR 1/2 fire traps or a Gelatinous Cube's engulf on a CR 2 acid trap. These are the base building blocks, but feel free to go nuts and get creative.