pika-labs Viral Hook
Prepends an extreme, no-dialogue ~4s hook to a user's video — an attention-grabbing event that erupts into the user's own scene, with an optional designed title burned into the lower third — then hard-cuts into the untouched clip.
generate_viral_hook does the whole render in one call and returns BOTH
the hook and the stitched final. This skill's job is the creative judgment the tool can't
make: read the scene, pick a hook action from the menu, and write a title.
Hook rules (govern what you WRITE as hook_action)
- Certain to grab attention, fast. Extreme and unmissable inside ~2s — over plausibility or relevance to the video's topic.
- Erupts into the user's OWN scene. Same person, location, lighting — the tool anchors on the best visual anchor frame: 0s when usable, otherwise the first detectable face frame. Describe the event entering THAT space, never a different setting.
- Use the scene's real geometry. Enter through a doorway with depth, a wall behind the subject, headroom above.
- No dialogue. Voice-free (only ambient / impact SFX) — don't write spoken lines into
hook_action.
Hook super-category menu
Four super-categories. Rotate super-category per run on the same clip/session — without rotation, regenerates collapse to vehicle / explosion / creature. Archetypes are starting points, not a closed list; invent freely within the category.
A. Destructive intrusion — external force violently enters and damages the scene
| Archetype | What happens | Scene affordance |
|---|---|---|
| Incoming vehicle | car / truck / bus smashes through a wall or doorway and barrels at camera | background depth or a back wall |
| Flash flood / wave | a wall bursts and water surges down toward camera | corridor / back wall |
| Structural collapse | ceiling / wall / shelf caves in, debris rains down | headroom / walls |
| Explosion / blast | fireball erupts behind them, shockwave + debris rush forward | a background surface |
| Creature attack | animal / monster lunges from off-frame or bursts in | open off-frame edge |
| Absurd intruder | dinosaur, elephant, UFO, giant hand enters behind them | background space |
| Natural disaster | tornado / meteor / lightning / sinkhole | exterior or large space |
B. Physics anomaly — laws of physics break, photoreal; scene + subject stay, motion goes wrong
| Archetype | What happens | Scene affordance |
|---|---|---|
| Gravity flips upward | subject, loose objects, and dust fall UP toward the ceiling | any indoor scene |
| Time freeze around subject | every other object holds mid-air while the subject keeps moving | scene with loose / moving objects |
| Magnetic pull from ceiling | hair, clothing, jewelry, small objects yank upward as if a ceiling magnet fired | indoor scene + loose props |
| Room rotates 90° | walls + floor rotate around the upright subject until "down" is now a wall | enclosed space, visible walls + floor |
| Object orbit | all small loose objects lift off and orbit the subject like a tornado | scene with props on surfaces |
| Inverted color flash | the scene briefly inverts to negative colors and back, like a glitch | any scene |
C. Content-supersized — an element FROM the clip appears building-sized and crashes in
Pull the element from the scene reading (Step 2) — hero product, pet, drink, phone, logo.
| Archetype | What happens | Source element |
|---|---|---|
| Giant hero product | the product being shown appears at 10× scale and smashes through the wall / ceiling | the product in the clip |
| Building-scale pet | the subject's pet appears at building height in the window / doorway | a pet in the clip |
| Giant drink | the cup / can / bottle becomes building-sized and tips over the room | a drink in the clip |
| Giant phone | the subject's phone scales up to fill the back wall, screen glowing | a phone in the clip |
| Giant logo | a brand mark on a wall / shirt / packaging grows to cover the back wall | any logo in the clip |
D. Content-projectile — a relevant object FROM the clip flies at the subject at speed
Source from the scene reading.
| Archetype | What happens | Source element |
|---|---|---|
| Hero-object slam | the product they're showing flies at high speed into their face | the hero product |
| Food / drink splash | their food or drink hurtles into them, splattering everywhere | food or drink in the clip |
| Swarm pelt | many copies of a small object (sneakers / pills / cans) pelt them like hail | a small repeating object |
| Prop whip | an object on a surface (mug, lamp, book) whips off and slams into them | any heavy prop visible |
Title rules (when the user wants one)
- ≤7 words, ALL CAPS, one punchy line. Tie it to BOTH the hook action AND the clip's actual content. Example: giant-sneaker projectile + sneaker unboxing → "THIS DROP HITS DIFFERENT."
- Optional — omit for a title-free hook.
- Typography defaults to bold distressed display type with a thick black outline. The user
may override via
type_style(a free-form style string) or by pasting abrand.md— extract ONLY the typography directives (fonts, weights, treatments), ignore logos / palette / voice. Warn that thin / un-outlined styles may wobble over the 4s.
Workflow
Step 0 — Intake (empty args)
If no video was provided, print this menu verbatim and STOP — do not call any tool:
What would you like a viral hook on? Paste any of:
- A local video path — e.g.
/Users/me/Desktop/clip.mp4- An https URL to an mp4
- A path + a title — e.g.
clip.mp4 — "YOUR PROMPTS WON'T SAVE YOU"- A path + "surprise me" — agent picks the hook action and title
Wait for the next message. Don't guess an input.
Step 1 — Get a URL
If the input is a local file, upload_asset it and use the returned
public_url. If it's already an https URL, use it directly. Any format is fine — no
transcoding or probing here.
Step 2 — Read the scene
analyze_media(video_url) → capture the subject + framing, indoor/outdoor + setting,
lighting, photoreal vs stylized aesthetic, and the spirit/topic. Also note the hero
objects (product, pet, drink, phone, logos), including whether each one is visible near the
opening or only appears later — required for super-categories C and D. This reading is passed
verbatim as the scene parameter.
Step 3 — Pick the hook action
Rotate super-category vs the previous run on this clip; pick a different one if possible.
Choose the strongest archetype the scene's geometry supports (A/B) or the most prominent hero
object (C/D). Write the specific hook action — entry vector + motion + scale + peak — as one
vivid sentence. This is hook_action. For C/D, name the exact hero object so the tool ties
it to the clip. If the hero object appears later in the clip rather than near the opening,
make the first hook frame explicit: "from the first frame, the subject is holding/using
[hero object]".
Step 4 — Title + style
Ask whether the user wants a title. If yes, propose a ≤7-word ALL-CAPS line tying the hook
action to the topic, get approval, and offer typography choices before rendering: default,
custom direction, or brand.md. If the user has no preference, use default and say so. If no
title is wanted, skip — the hook renders title-free.
Step 5 — Render
Call generate_viral_hook({ video_url, scene, hook_action, title?, type_style? }).
If it returns {task_id, status}, poll task_status(task_id) in a tight
loop until terminal, then read the result. On failed, surface the error — don't retry blindly.
Step 6 — Deliver
Present both clips:
- hook only:
[[video:<hook_url>]] - final stitched:
[[video:<final_url>]]
What NOT to do
- Don't re-implement the render in the skill. No extract_frame / generate_image /
edit_concat / transcode here —
generate_viral_hookowns all of it. If the hook looks wrong, change thehook_action/titletext, not the pipeline. - Don't pass a seed. Variations should come from
hook_action,title, ortype_style. - Don't bake a title onto the real video. The title belongs only on the hook.
- Don't auto-edit an approved title. If a rephrase is needed, ask.