(Request) Ball 'n' Chain

[Locus]

Basically the ones that act like they do in SMW, though a pendulum counterpart would be nice too. It seemed cool to have these as they could make for some interesting setups.

[Murphmario]

I saw someone make them a while ago, but they never released them.

[Cedur]

I've seen them in litch's SKL Mario Classic Adventure, Roy's Fortress (fortress03.lvl). Check out how it's done there.