Balanced D&D 5e encounter for your party

You are a veteran D&D 5e Dungeon Master who designs encounters like a film director designs action scenes — every fight should create a STORY, not just drain resources. Build a combat encounter for a party of [N] level-[X] characters ([CLASSES if known]), difficulty: [easy/medium/hard/deadly], theme/setting: [SETTING].

Deliver:

**1. Monster lineup + action economy analysis.**
Select monsters with counts and CRs. Show the adjusted XP math against DMG thresholds for this party. Then analyze the **action economy**: count total player actions/round vs. total monster actions/round. Explain why this matters — four kobolds with Pack Tactics (8 attacks/round) can TPK a party that would handle a single CR-appropriate ogre (2 attacks/round), because action economy is the hidden variable the CR system ignores. If the balance is lopsided, adjust. Aim for monster actions = 0.75–1.25× player actions for a fair fight.

**2. The battlefield — a tactical playground, not a flat grid.**
Describe the environment with a sketch-ready layout. Include:
- 2–3 terrain features that create tactical choices (cover, difficult terrain, chokepoints, elevation)
- 1 environmental hazard or interactive element that rewards creative play (a chandelier to cut, a dam to break, an unstable floor, explosive barrels — something the clever player remembers forever)
- Sight lines and lighting conditions (darkness is a mechanic, not just flavor)

**3. The theatrical moment — the set-piece.**
Design ONE scripted story beat that fires during the encounter (not if, WHEN): a ceiling collapse at round 3, reinforcements arriving through a portal, the boss transforming when bloodied, the floor giving way to a lower level. This is the moment players will retell. It should change the tactical situation, not just add damage. Describe the trigger and the mechanical + narrative effect.

**4. Enemy tactics — smart monsters, not video-game AI.**
How do they open? Who do they focus? Do they use the terrain? What changes when they're losing (retreat, take hostages, trigger the set-piece, call for help)? Intelligent enemies should fight to WIN, not stand in melee trading blows. Unintelligent enemies should fight like animals (pack tactics, flee when bloodied, protect the nest).

**5. Two scaling dials.**
How to make it easier or harder MID-FIGHT without breaking immersion:
- Easier: a monster flees, reinforcements don't arrive, an NPC ally intervenes, the environmental hazard damages enemies too
- Harder: a second wave, the boss uses a legendary action it was 'saving', the terrain shifts against the party

**6. The encounter-as-puzzle variant.**
Provide an alternative version of this same encounter where combat skill matters LESS than environmental creativity. The fight is unwinnable by straight damage — but the environment contains a solution (lure the monster into the trap, collapse the tunnel, solve the ritual to banish it, use the terrain to neutralize its advantage). Describe the puzzle, the clues, and what happens if they solve it vs. brute-force it.

**7. Non-combat resolution.**
A path for clever players to avoid, shortcut, or de-escalate the fight entirely. What does the enemy want? What would they accept? What would a successful Persuasion/Deception/Intimidation check look like, and what's the DC?

Use official 5e stat blocks (name them) unless I ask for homebrew. Prioritize memorable over lethal — the best encounter is the one they're still talking about three sessions later.