Silly Pink Balloon

There are two sources and both need something to happen first. The Party Girl stocks them, but only while a party is actually running, so you either wait for one to fire on its own or throw one yourself. Balloon Slimes drop them too, which is the faster route if no party is due. Buy more than the build needs, because the balloon furniture recipes eat into the pile.

They behave like Pink Slime Blocks underfoot: land on one from any height, take no fall damage, and get thrown back up. A single layer at the bottom of a hellevator turns the whole shaft into a safe drop, and that alone justifies keeping some in the inventory. Placement has a quirk worth planning around. Identical colors merge into one large balloon shape, while a different color set beside them refuses to join and stays a separate round blob. Alternate colors for a lumpy cluster, stick to one color for a smooth surface.