Snow golem oozing slime farm

The original oozing slime farm, the design the other snow golem builds copy. A dispenser drops carved pumpkins onto snow blocks you place by hand, each new golem shoving the last one along a row of fences, and once they are stacked up a second dispenser splashes the whole line with a potion of oozing. The golems die into slimes, the slimes die in the chamber below, and you get slimeballs and XP out of it. There is an optional crafter and shulker box loader on the end to pack the slimeballs while you run it. It is Java only, and it is a burst farm: a run lasts as long as the snow you brought and every block goes down by hand.

Rebind place to another key and hold it down rather than spam clicking. Golems placed too slowly fall through the fence and burn on the campfire, and that is the single most common failure.
Put obsidian or another immovable block behind the fences so the pistons cannot shove them out, and move the button on the oozing dispenser out of the way.
Swap the campfire for a wall or a fence post and let the water kill the golems instead. canitbeapplied2500, jordibuchner and martinbarman8482 all landed on that fix.
serphal traced the jamming to the pumpkins not getting back to the dispenser. Raise the walls around the water at the top, keep a buffer of pumpkins in the dispenser, and check the killing chamber for the ones that fell in.
Hauwerd swaps the walls for decorated pots so the slimeballs stop ending up in with the snowballs.
On paper servers and their forks ghost blocks make the dispenser misfire. Place slower and put chests behind the fences so a jam does not tear the farm apart.