The Setup Box Details

(Written for Level 6 Characters, easily adapted for all levels)

The box has 10 STR/DEX/CON, and 0 INT/WIS/CHA, AC 20, HP 10.
The entire Ship's hold is full of 20 barrels of Wildfire. The barrels
are mostly stable, but will detonate if exposed to fire. Each bar- The instant it is opened or "senses" distress, the box "casts" Delayed
rel will deal 8d6 of damage in a radius of 20+1d20*5 feet. Blast Fireball (DC 15) with Extended Metamagic and the gem starts
visibly blinking/ticking.
There is a large ornate chest in the middle of the room with a fist-
sized gem inside of it visible through a glass/invisible membrane. For extra flavor, quietly increase the radius by 1d6 ft every round it
doesn't detonate.
The interior of the box is lined with an anti-magic field, so spells
or physical objects cannot penetrate the interior of the box with- For all intents and purposes the Box is "Concentrating" on the spell,
out it being opened first, as the field hinges with the lid. and upon taking damage makes a concentration checks like any
other creature. Once concentration is dropped, the spell ends and
To defuse the bomb, the gang need to successfully defeat the the gem detonates.
locks on the box, open it, then remove the blinking gem or cast
Dispel Magic on it. If it is destroyed, it loses concentration and the bomb goes off. If
PC's remove the blinking gem from the box, they must make DC 10
Gently touching the window does nothing other than show it to be DEX Saves per the rules in Delayed Blast Fireball.
solid glass. Casting a spell on the box powers on the device.
Box Variations:
If you're real mean, put a glyph of warning under the box (Investi- Tiny Box:
gation to find) that triggers the bomb to start ticking if its removed.
They've still got a minute to defuse it, so they're probably fine... Each turn the carrying player must make a DC 15 Acrobatics or
Sleight of Hand check as their action to protect the fragile wires and
Players can attempt to carry the box to a safe distance. While instruments. Failure means DC 20 DEX save to not drop it, triggering
holding it, if they take damage, they must make a CON save simi- the bomb.
lar to Concentration, (Half damage taken, MIN DC 10) or they
drop the box. They repeat these checks every turn they are carrying it and it is not
actively blinking.
DC for most saves and checks = 15 or 12+Proficiency unless
noted otherwise. Medium Box:

The box is 200+lbs and is clearly designed to be carried by two

Opening the Box medium sized creatures. Each carrying creature must use their ac-
tion to make Athletics checks that combined must total a DC 30 to
Two Keys: This works like a Safe Deposit Box. Players need move the box their full movement.
two particular keys turned at the exact same time (One creature
readies an action to turn on the other's initiative). Players can find - If they beat a 20, they get it there safely, but only half their move-
one or both keys through RP Shenanigans. Alternatively, PC's ment. (This lets the Barbarian rage and solo carry the thing too).
can cast Knock or Pick the Lock, but they must both succeed at
the same time or else the box starts ticking. - Less than 20 and they need to make a DEX save to not trigger the
detonation process right there.
One Complicated Key: PC's need to acquire one elaborate key
from an NPC, or make three consecutive Lockpick checks as - Less than 15 (combined still) and the the bomb is activated.
three separate actions. There is only room for one person in front
of the locks, and they cannot stop and restart the process, so one
character must make three consecutive lockpicks in a row. (Thief
Rogues or Action Surging Fighters can actually make 2 checks in
a turn).

The first "tumbler" is DC 15, the next is DC 20, the last is DC 25.
Failure on any check means the picker has to start picking the
locks all over again. Again, Knock works here too, but it does
mean burning three spell slots as three actions on three separate
locks.

Failing any lockpick check by 5 or more triggers the bomb's acti-

vation. One creature may use Help to grant advantage, and it's a
great time to use boosting spells like Bless or Guidance.

Failure by 10 or more and the Thieves Tools break. Fail a DC 10

DEX save and they break in the lock. Mending can fix the tools,
but that's going to be a very long minute.

Defusing the Bomb

Once the box is open, any caster can foil the detonating bomb
with a DC 17 casting of Dispel Magic. Alternatively, players can The Bomb
grab the gem (with DEX Saves per the spell) and throw the gem
sufficiently far away from the exploding barrels. The bomb was created by an artificer who has modified the magic of a
Delayed Blast Fireball.
The Barbarian solution is actually more viable here. They can
reasonably carry the bomb somewhere safe, smash the crate to If the case is properly unlock, it can be removed using DC 15 Sleight of
pieces, which will activate the bomb on the first round or two of Hand checks to put it somewhere safe.
it's activation, dealing a very survivable amount of damage.
....So long as they are far enough away from the Wildfire barrels. It is wired to detonate in 2 minutes, or in 20 rounds when it maxes out
at 24d6 to all creatures within 40ft. DC 15 DEX Save for half.
Should be good for getting the palms sweaty. In the spirit of fair
play, roll for Initiative when they go to pick the bomb (or just let However, the first round it is blinking, it will only deal 4d6 damage to all
players pick their turn order), setting the Bomb on Initiative 0. creatures within 20ft. Still enough to instantly trigger the Wildfire if
nearby.
Be extra explicit on where everyone is and isn't so there's no
surprises when someone is caught in the blast radius, or was so Each round the bomb grows it adds 2d6 to its damage, and 5ft to it's
far back that they needed a Dash Action to get there and can't explosion radius.
cast Dispel Magic this turn.
Handling the blinking activated crystal follows the same procedure as
the normal spell.

Arcana identifies several things at varying DC's:

10 Spots the gem as an evocation spell that can be dispelled.

12 Spots the anti-magic field protecting it. DC 20 to dispel the field.
15 Spots that casting anything on the box triggers it.
17 Clocks the Spell as a modified Delayed Blast Fireball.
20 Clocks the Spell's range modification, and it's starting size.
25 and the PC's will know the exact size and damage every round.