What it is. You push a sticky ball. Anything smaller than the ball sticks and adds to it. It grows, so the threshold rises, so bigger things stick — until a katamari that started eating thumbtacks is eating cows, then houses, then clouds. One verb, run against a clock.

Player fantasy / why it’s fun. The world is one continuous ramp of loot, and you are the loot funnel. Every second, something new crosses the threshold from scenery into snack. The joy is not skill — it’s recontextualization: the desk you couldn’t dent is now a crumb. See pattern-escalation-and-payoff, pattern-surprise-and-delight.

Design DNA

The compressed essence — three gears, nothing else:

• Absorb-to-grow. Contact + size(object) < size(ball) → attach. One rule, applied uniformly. See mechanic-grow-shrink, mechanic-merge.
• Scale that recontextualizes. Growth doesn’t add stats — it redefines the object taxonomy. The same object flips from wall → obstacle → snack → dust as you cross its size band. The world is authored once; scale re-reads it.
• The timer. A clock turns “roll around forever” into “how big can you get.” It makes every skipped item a cost and every dense room a jackpot. See pattern-pacing-and-tension, system-session-structure.

Kill any one gear and it collapses: no threshold → no arc, no scale → no wonder, no clock → no tension.

Load-bearing structures

What to steal

• The single verb. Resist adding a second interaction. Katamari has no attack, no jump, no menu-in-the-moment. The whole design budget goes into what the one verb touches. See process-pillars, antipattern-feature-soup.
• The exponential payoff. Reward should feel like an order-of-magnitude jump, not +1. Tune bands so each unlock re-opens the map. This is the incremental-genre dopamine loop wearing a physics costume — genre-incremental, system-resource-loops.
• The “what can I pick up NOW” pull. After every growth tick, the player’s eyes re-scan the room for the newly-eligible. Design rooms so a size-up reveals a fresh layer of targets sitting in plain sight the whole time. See pattern-surprise-and-delight.
• World authored once, re-read by scale. Cheapest content multiplier there is — a single dense scene yields minutes of escalation. See system-procgen-design, pattern-emergence.
• Threshold friction as feedback. Too-big objects bounce you and knock stuff off. Loss is legible and comedic, never a wall. See pattern-fairness-and-trust, pattern-anti-frustration.

What’s just theme (drop it)

• The King of All Cosmos, the cousins, the story of the stars. Charming, orthogonal. The verb survives without narrative — see world-tonal-juxtaposition if you want your own flavor.
• The exact object list (sushi, sumo, pandas). The absurdity is load-bearing — do NOT drop the tonal whiplash of eating a whole town. But the specific props are swappable. Pick a domain where scale escalation is inherently funny or awe-inducing; keep the whiplash, change the nouns. See world-theme-vectors, world-mood-and-atmosphere.
• Twin-stick tank controls. A period artifact, not the design. Any push-a-ball control works; simpler is better. See system-camera-and-controls.

Do not drop: the timer, the uniform threshold, the exponential bands, or the absurd scale jump. Those four are the game.

Composes into

• genre-physics-arcade — the native home; contact-driven, forgiving, feel-first. Verify feel there.
• genre-incremental — Katamari is a clicker with a camera. Growth-per-second, unlock-gated content, number-go-up made spatial. See system-resource-loops.
• genre-horde-survival — swap “absorb props” for “absorb XP/enemies” and you get the anchor-vampire-survivors snowball; same escalation spine, combat skin.
• genre-sandbox-survival / genre-management-tycoon — the “grow your footprint, the map re-reads at each tier” loop generalizes to base and colony scale.
• Feeds system-collectibles, system-session-structure, system-reward-schedules as a self-contained loop kit.

Twist seams

• Katamari but you shrink and the world grows around you (perspective) — invert the verb: you shed to slip between molecules, and the “world” is a cell, a circuit, an atom. Same recontextualization, run downward. The dread/wonder flips: scale becomes claustrophobia. See mechanic-grow-shrink, world-tonal-juxtaposition.
• Roll-and-grow but you must shed mass to fit through gates (constraint) — add a subtractive verb. Doorways, pipes, and sieves gate on max-size, so hoarding is punished and deciding what to drop becomes the skill. Turns a flow toy into a genre-grid-puzzle-adjacent optimization — pattern-risk-reward, system-resource-loops.
• Absorb-to-grow but the world absorbs YOU back (threat) — bigger entities roll too. Now it’s a food-chain arena — an agar.io out of Katamari’s guts. See system-enemy-ai, pattern-pacing-and-tension.
• Grow-by-absorbing but only matching types stick (filter) — add a mechanic-merge color/category rule. Now routing matters: a red ball needs red mass, so the map becomes a sorting puzzle wearing an arcade skin. See genre-match3.

See also

• anchor-vampire-survivors — the other great “snowball a single number” anchor; steal its escalation, skip its combat if you want pure Katamari.
• anchor-tetris / anchor-peggle — single-verb physics-arcade clarity; how one rule carries a whole game.
• mechanic-grow-shrink, mechanic-merge, mechanic-magnet, mechanic-stack — the mechanical parts you’ll wire.
• genre-physics-arcade, genre-incremental, genre-horde-survival — where this DNA lands.
• pattern-escalation-and-payoff, pattern-surprise-and-delight — the two patterns doing the emotional work.
• process-the-twist — start from the verb, twist one vector, don’t survey the corpus.