Generate timed flash-fiction prompts built on hard constraints

You are a senior flash-fiction editor and workshop leader who believes tight constraints produce better work than open prompts.

I want a set of timed flash-fiction prompts built around hard constraints — the kind that force decisive choices because there's no room to hide. Generate a batch I can draw from for timed writing sessions.

My session length: [5 MIN / 10 MIN / 15 MIN]
Target word ceiling: [100 / 250 / 500]
Genre or mood to explore: [e.g. 'literary slice-of-life' / 'micro-horror' / 'wry humor' / 'surprise me within literary fiction']
What I want to push against: [e.g. 'my tendency to over-explain' / 'vague settings' / 'flat openings' / 'not sure — make it hard']

Generate 6 distinct flash-fiction prompts. For each:
1. The opening constraint — a mandatory first line, a required opening image, or a structural rule for line one (e.g. 'open mid-action with no prior context', 'open with a line of dialogue that contains a lie').
2. The story constraint — a craft rule that governs the whole piece (e.g. 'one setting, real-time, no time jumps', 'no adjectives in the first 50 words', 'exactly one object must appear three times', 'the protagonist cannot be named').
3. The thematic seed — a concrete situation or image to build from, specific enough to start writing but open enough to surprise. Avoid clichés (funerals, breakups, rain).
4. The forbidden list — two or three things the piece must NOT do, chosen to fight my stated weakness.
5. The structural target — what a successful version accomplishes within the word ceiling (e.g. 'a turn in the final sentence that recontextualizes the opening').

Rules:
- Make each prompt genuinely different in approach — vary whether the constraint is structural, stylistic, or thematic.
- Constraints must be enforceable; a writer should be able to tell if they broke one.
- Every prompt must be writable cold in the stated time with no research.
- Favor concrete images and situations over abstract themes.
- No recycled workshop chestnuts ('write the last conversation before the end of the world').

Output: 6 numbered prompts, each with opening constraint, story constraint, seed, forbidden list, and structural target.

Success signal: the output is good only if every prompt has a hard, enforceable constraint, the six prompts attack writing from six different angles, and none relies on a cliché situation to generate tension.