How can a BBEG deal with a Wall of Force and Sickening Radiance spell combo without trivializing it?

This question has already been asked in general form here, but was closed as too broad: "How to deal with broken combos?". I’m going to make an effort to make the scenario I’m asking about more specific to keep my question open.

The spell sickening radiance (XGtE, p. 164), cast just before a wall of force (through a readied action or something similar) can trap and kill many solo Big Bad Evil Guys (BBEGs), with just two casters. This combo is particularly lethal because of the levels of exhaustion the spell gives, but could work even with other persistent damage spells. Sickening radiance is a spell that creates a persistent area of effect for 10 minutes that deals radiant damage and gives exhaustion on failed saves.

The combo works like this: wall of force (WoF) caster readies their action, with the trigger "cast WoF on the BBEG when my friend casts sickening radiance (SR)". SR caster’s turn comes, and they cast SR, centered on the BBEG. WoF gets cast on the BBEG as a sphere, trapping the BBEG within the wall of force for 10 minutes while they get exhausted to death.

What actions can I, as a DM, take to make a fight with a BBEG not as trivial, while still rewarding the two spellcasters’ ingenuity?

I classify "rewarding the two spellcasters’ ingenuity" as at least forcing the BBEG to spend a limited resource to deal with the problem. So a BBEG having disintegrate is one option for what I can do, but giving the BBEG a teleport as an action (or legendary action) is not.

Will a Contingency/Dimension Door combo save me from breaking a Staff of the Magi?

My wizard has a Staff of the Magi one and is itching to break it over his knee. But he values his life and wants to maximize his chance of survival. If he casts Contingency with Dimension Door – specifying a location far enough away from the blast – there is an argument that the spell goes off before the explosion or possible Plane Shift. How would you rule?

Is it possible to combo the spells Create and Destroy Water, Shape Water, and Lightning Bolt in order to make LB more powerful?

Asking on behalf of the group’s Wizard. He wants to electrocute the BBEG and have the spell deal extra damage through clever use of game mechanics. As a DM, I am all for it, as long as the rules somehow support it.

Create Water. You create up to 10 gallons of clean water within range in an open container. Alternatively, the water falls as rain in a 30-foot cube within range,* (PHB pg. 229)

Is this something you could cast, and either cast Lightning Bolt (8d6dmg) on the target being rained on(on your next turn / action), or use Shape Water to form a cube around the BBEG, and then Lightning Bolt to the face?

I personally think something being wet is conductive, which I might say means that the target being rained on would have disadvantage on the saving throw. My player really wants to try and argue that being wet yields a Damage Vulnerability (2x dmg), therefore causing lightning bolt to deal (8d6)*2 lightning damage.

Is there a rule I haven’t found in the PHB about this already? I do really want the player to feel cool, especially since this upcoming week there is a BBEG confrontation and this might turn the tide for my group.

Does Green Flame Blade and Sweeping Attack combo cause the bonus effect of GFB to hit again?

So I was theory crafting and I came across the combination of Green-Flame Blade with the Battlemaster Fighter’s Sweeping Attack maneuver. I understand that just fine. What I am unclear on is this:

I cast GFB and hit target. Then I activate SA to roll Superiority Dice to hit a second foe for the Dice’s damage (If the original attack would hit the second foe’s AC).

So I end up with one melee weapon attack that hits two different foes with special effects added to the attack. So it should look like this correct?

Weapon damage + GFB damage. GFB Jump damage to second target. Superiority Dice damage + GFB damage (because it is still the same attack correct?). GFB Jump damage to another target (possibly the original) ((because it states that this happens on a hit with an attack?)).

What exactly is a “Combo List”, and why is this site providing them for free?

After asking for e-mail lists the other day, I got linked to this:

This is a very strange "blog" which appears to be regularly publishing (or linking to, rather) lists of e-mail addresses which have supposedly been leaked in data breaches. I have no interest in the passwords, but it seems to also include those. I’m not sure if those are really the passwords to the e-mail accounts, or passwords for something else entirely.

My interest in this has nothing to do with using somebody else’s e-mail account.

They don’t mention what a "combo list" is, and I cannot figure this out from searching or thinking. It seems like the blog assumes that everyone knows what it is.

I also thought it was a fake site at first, but eventually did manage to download a list, and it appears real. But then again, who knows what kind of information really is in those lists?

I basically wonder why anyone would run such a site, and regularly update it. Why would they give out this info to the public like this? What’s in it for them? Why would they want more spammers to send e-mails to these victims of data breaches?

What is the lowest-level spell combo to give disadvantage to an enemy’s specific save, without running into follow-up concentration issues?

What I’m trying to do is debuff an enemy’s stat so that I can hit them with a “save or suck” spell like dominate monster, and be more likely to succeed.

The problem is, I’m running into concentration issues because most spells that debuff a single stat like Bestow Curse use concentration, and thus I cant use them in conjunction: The moment I cast Dominate Monster, Bestow Curse is removed.

Hex also will not work because it only impacts ability checks, and not saves.

To clarify, I am a Warlock who wants to cast powerful disabling spells only when they have a high chance of success (so typically Wisdom has to be the weakened modifier). However, I am open to answers outside of that class, as well as any spell combos that specifically function as

  1. Weakening the the ability save for the second spell without utilizing concentration, and

  2. The second spell being a powerful, one-save spell of concentration.

What spells would be the best for this kind of combo, given that only I can cast the spells?

Novice question: Limiting number of combo attempts with Fail2ban and 128 bits of entropy

Apps such as Fail2ban and DenyHosts enable unix administrators to limit username/password combo attempts to typically 3 attempts. But why 3? Some admins enable more, like 6 or 8 giving honest users a little more slack when making different attempts at a password they may not recall exactly. But why not 18? Or even 30?

If a sophisticated cracker wanted to brute force a combo with a scheme involving 128 bits of entropy, s/he would need to make trillions of attempts a second. So if an admin limited the total number of attempts to 100 using Fail2ban, wouldn’t the authentication system still be secure and robust, as long as the admin sets up their username/password scheme to require 128 bits of entropy?

Vampire the Masquerade – Can the effects of the combo discipline Bliss stack?

The combination discipline Bliss (V20, Lore of the Clans, Dominate ••, Presence •••) is described as allowing any virtues for a willing target to be temporarily raised on a successful roll. It doesn’t appear to describe any limitations, other than the increase is “by a single dot, up to a maximum of five dots” and “Only one Virtue can be increased at a time.”

That “only one can be increased at a time” seems to imply that multiple virtues can be increased with multiple applications, but considering that this doesn’t require the expenditure of Willpower or any specific length of time, it would seem like it’s a fairly low-level combo discipline to have the actual capability of giving a target maxed out Conscience, Self-Control, and Courage in exchange for essentially just meditation on a work of art for a few minutes.

Can anyone chime in with a good reason why a Toreador with this power wouldn’t be able to compile a virtuous mix tape to listen to every evening after waking up so they can roll to max out all of their virtues?

Sidenote: I’d like to introduce an NPC into my game with this power, and I’m anticipating my players asking whether or not the effects are one-use-only or stackable. I can think of a bunch of interesting ways to house-rule this to avoid abuse (like every virtue raised after the first makes the target lose a point of Willpower), but I’m curious if there’s a rules-as-written limitation that I’m overlooking.