Bursting into the chamber, your triumphant shout of “I have you now, villain!” dies in a surprised gasp. This room is a mass of turning cogs, swinging pendulums, and immense gears. Your enemy laughs, ducking behind a giant spring and into an obscuring burst of steam. “Foolish heroes,” he says. “I told you that my plans always run like clockwork. Well, here it is!”

The Watchmaker’s Lair is filled with dangerous clockwork devices. These are hazards rather than traps, as they operate regardless of the characters’ presence and no Perception check is required to notice them. This makes them no less dangerous, especially when combined with appropriate enemies.

In a giant clocktower, on the Plane of Gears, or in the hollow heart of a colossal golem, the Watchmaker’s Lair provides numerous encounter groups to challenge PCs. Not to mention flinging, smashing, or crushing them. [More…]

ENCOUNTER GROUPS
Athletic Elite or Solo monsters compliment these hazards nicely, as their large hit point totals allowing time for the fight to rove around the chamber. Flying monsters or those with the Skirmisher role can make especially good use of the odd terrain and impeded PC movement. Powers which Push or Pull opponents are especially useful.

The Watchmaker’s Lair works well with a large number of minions, who die spectacularly when they fall off pistons and into grasping cogs, or are caught in an explosion of gears. The fragility of minions allows creative PCs to use the hazards offensively — tripping, throwing, and bull rushing enemies into the clockwork.

Level 3 Encounter (XP 816)
 7 Kobold Minions (level 1 Minion)
 2 Kobold Slingers (level 2 Artillery)
 2 sets of Grasping Cogs (new level 4 Obstacle)
 2 Gear Bursts attached to the Grasping Cogs (new level 2 Hazard)
 6 Grease Patches (new level 3 Obstacle)
 Steam Piston (new level 6 Obstacle)

Level 5 Encounter (XP 1078)
 4 Deathjump Spiders (level 4 Skirmisher)
 6 Steam Pistons (new level 6 Obstacle)

Level 7 Encounter (XP 1550)
 Young White Dragon (level 3 Solo Brute)
 Horologic Pendulums (new level 6 Elite Obstacle)
 Treacherous Ice Sheet (level 5 Obstacle)

Gear Burst Level 2 Blaster

Hazard XP 31
Clunks, rattles, and the scream of twisted gears grab your attention. A blast of steam heralds the sound of metal tearing free from metal: An explosion of shattered cogs and broken springs.

Machinery that can cause a Gear Burst occupies 1 square. This hazard can be added to any clockwork mechanism or construct.

Trigger: Whenever a physical attack or spell whose keyword is a physical effect (force, thunder, etc) misses a target on or adjacent to this hazard, there is a 1 in 6 chance that the attack hit the hazard instead, and triggers a Gear Burst on the same initiative score next round. Delaying (not disabling) a clockwork device with the Thievery skill can also trigger a Gear Burst, unless the skill check beats the DC by 5 or more.

Attack Immediate Interrupt
Target: Close Burst 1
Attack: +5 versus AC
Hit: 1d6+4 damage

Countermeasures: A Gear Burst can be disabled with a DC 15 Thievery check applied in the round before it activates. A roll of 10 or less results in the burst going off immediately.

Encounter Uses: Gear Bursts occur when a clockwork mechanism is damaged or prevented from working properly, such as by a Thievery check to delay a hazard’s effect. It can also be used in place of the ‘trigger trap’ result of a failed Thievery check on appropriate devices. When attached to a construct, the chance of a Gear Burst makes melee with the creature considerably more dangerous. Each explosion also damages the construct however, whose delicate innards take double normal damage from the burst.

Grasping Cogs Level 4 Obstacle

Hazard XP 44
The floor is a mass of interlaced cogs, their teeth grinding together like the blunt fangs of a hungry monster. A misstep into them could crush your foot to pulp.

Grasping Cogs occupy any 4 contiguous squares, and count as Difficult Terrain. Cogs may be set horizontally (forming part of the floor), or vertically as a moving wall about 3 feet high, which can provide cover.

Trigger: Character enters or begins their turn in a hazardous square

Attack Immediate Reaction
Target: Creature on hazardous square
Attack: +7 versus Ref
Hit: 1d6+4 damage per round and the target is Restrained. At the DM’s discretion a foot injury halves the victim’s speed for the rest of the encounter.

Countermeasures: Characters can leap over this hazard with a DC 20 Athletics check, or jam the cogs with an appropriate tool and a DC 17 Thievery check. A Restrained character can be freed with a DC 12 Thievery check or a DC 17 STR check.

Encounter Uses: A maze of Grasping Cogs help enemies avoid melee-focused PCs. Skirmishers and creatures with Push/Pull abilities are especially dangerous when used with this hazard, as are flying opponents. Small characters can use a set of vertical cogs to hide from opponents and provide them with cover. Adding nearby Grease Patches (see below) increases the chance of characters accidentally stumbling into the cogs.

Grease Patch Level 3 Obstacle

Hazard XP 38
Slippery grease is smeared over the area.

A Grease Patch covers 1 square and counts as Difficult Terrain.

Perception
DC 10: Something is smeared on the floor
DC 15: It as a thick layer of grease.

Trigger: Creature entering or beginning its turn in a grease patch.

Attack
Opportunity Action (Melee)
Target: creature in the square
Attack: +6 versus Ref
Hit: Target falls prone and is pushed 1 square in their direction of movement. Characters that were running are pushed 1d3 squares instead. If the target is already prone there is no push effect but their turn ends immediately.

Countermeasures: A DC 15 Acrobatics check allows a character to move across the square safely.

Encounter Use: Grease Patches can be used to push characters into other traps, such as the Steam Piston or Grasping Cogs. Entirely covering an area in this hazard can add a comic dimension to a battle against numerous minions and brutes.

Horologic Pendulum Level 7 Obstacle
Elite Hazard XP 600
This huge pendulum swings back and forth across the chamber like a gigantic crocket-mallet. Each change of direction is accompanied by a thunderous clunk from somewhere up above.

Marking time for a clock mechanism high above, the Horologic Pendulum swings back and forth through a 2 square wide row of 10 squares. It is effectively two hazards in one: On its turn the pendulum makes an attack against every creature in its path, and then a second attack as it swings back in the opposite direction.

Trigger: The pendulum swings each round with an initiative of 10

Attack
Standard Action (melee)
Target: Every target in the pendulum’s area, from one side to the other. Then a second attack in the opposite direction.
Attack: 2x +12 versus AC
Hit: 2d6+5 damage and target is pushed 2 squares in the direction of the pendulum’s swing
Secondary Attack: +10 versus Fort.
Hit: Target is Dazed (save ends)

Countermeasures: Stopping or detaching the pendulum requires a DC 20 Thievery check (only possible if the character has access to the mechanism at the top of the pendulum). Its motion can also be stopped with a DC 30 STR check.

Encounter Uses: A series of pendulums swinging on different initiative scores can form a layered barrier and provide cover to those behind them. Bisecting the pendulum’s course with other traps makes it particularly effective. The Restraining potential of Grinding Gears makes for an especially dangerous combination.

Steam Piston Level 6 Obstacle
Hazard XP 63
Set into the floor is an oiled brass column, which surges violently up and down every few seconds in a gout of steam.

The steam piston is a circular column occupying a close burst (9 squares). Every round it shoots up to a height of 20ft, slams to a halt, and crashes back down to the ground. It begins each round level with the floor but blocks movement and line of sight for the rest of the round after it activates.

Trigger: The piston activates each round an initiative of 15.

Attack
Standard Area (close burst 1)
Target: All creatures on the piston
Attack: +7 versus Ref.
Hit: 1d6+4 damage and the target falls prone. If the attack hits by 5 or more, target tumbles from the piston as it reverses direction. The character lands in a random square adjacent to the piston and takes 2d10 falling damage.

Countermeasures: The piston can be deactivated using a series of nearby valves and levers (Thievery DC 12), but jamming an individual piston’s movement is exceptionally hard (DC 22).

Encounter Uses: Multiple pistons placed next to each other allow enemies to engage in combat as they rocket up and down. If placed in series they can be used as stepping stones to reach higher levels, or individual pistons can help launch a character into the air: They provide a +10 bonus to athletics checks made for vertical leaps. Surrounding a piston with Grease Patches (see above) increases a passing character’s chance of accidentally sliding onto it.