basketballs?

Roughly a foot in diameter, these (sometimes rocky) spheroids have 2-4 wispy appendages.

• roughly basketball sized - range from grapefruit to beachball
• crusty, stone exterior, or fleshy gasbag - caste system?
• tentacle-like arms
• no obvious fingers, but grip by wrapping appendage
• stubby feet, no perceptible leg or toe
• On death, the rocky shell deflates. If heat-based, internal gasses explode - what about the non-rocky ones?
• communicate through whistles, trills, pops, clicks, etc

Technology:

• harpoon tubes: projectiles generated in cylindrical shell of tarnished metal, several blinking lights/diodes. No obvious trigger. Harpoon disintegrates into ash shortly after contact. Rho found a working one, but left it behind after it fired accidentally.
• Hive fiber: fleshy ball-boys live in a spherical