Not only do the coal lumps look heavy for them tiny things, they're actually heavy enough that Chihiro, the girl in the movie, has difficulty carrying one of those. So I guess these soot balls are very strong compared to their size.
They're just so cute!
English Version (well mine anyway) is also Susuwataris.
Either way instant love! I love Studio Ghibli! Some variations in the coal would be nice but still awesome!
Isn't that what they're called in the English version, though? 
I didn't know what their official name was. In french they are called "noiraudes" in My Neighbor Totoro, but I didn't know how to translate it so I just called them soot balls, because... basically that's what they are :p
Thanks for letting me know :)
Awesome as hell-- I love these little guys-- they scared the everloving SHIT outta me when I was a kid watching My Neighbor Totoro.
I've never heard them called soot balls. Is that what Susuwataris are supposed to be?
Well the coal is heavy for such little fellows, they can't move really fast :p
I don't know if you've seen the movie, but they move the same way in it.
It's very good, but why do they move so slow? @_@
It's like they're strutting their stuff while carrying ther coal.
One of my most favorit movies!