Hullspark Cat Dance

You put a disc in a jukebox next to your cats and nothing happens: parrots dance to the music, cats just sit there.

Where: in the world, on any cat within about 3.5 blocks of a jukebox that is playing a disc (the same distance the game uses for a dancing parrot).

What you can do: nothing to learn. Put a disc in the jukebox. Standing cats, sitting cats and kittens hop, lean from side to side, nod their heads and swish their tails to a steady beat; the dance eases in over about two thirds of a second. Take the disc out, or let the song end, and they ease back to their normal pose. If you were too far away to get the game's "stop" message (it reaches about 64 blocks), the cats still stop when you come back: a jukebox without a disc, or one whose area was unloaded, no longer counts. Cats that are lying down or resting keep their own pose. Other animals are untouched.

It only changes how the cat is drawn on your screen: no entity, no AI, no saved data and no packets are touched, and there are no new textures or sounds. Other players do not see it unless they have the mod too.

/catdance on|off|status switches it (a client command, not sent to the server). config/catdance.properties: enabled, and strength from 0.3 (small) to 2.0 (big), 1.0 normal, read at game start.

Result: in the automated test (a real game window, a flat test area with a jukebox and cats), putting music_disc_cat in made the 4 cats in range (standing, sitting, kitten, one at 2.4 blocks) reach full dance while the cat 4.0 blocks away stayed still; five screenshots differed from the quiet picture and from each other; /catdance off gave back the quiet picture exactly while the music kept playing; taking the disc out, and letting the song run out by itself, stopped the dance and gave back the quiet picture; with the song ended on the server while the player was 700 blocks away, the cats did not dance when the player came back. With the mod switched off the same test fails (12 of 34 checks).