The artist, S. Anomalous, calls them "latex monocle prosthetics" but these monocles are handmade artworks. Besides the bony hand you see here, there are models featuring Cthulhu, skulls, gears, lions, mythological figures, and other motifs. The lenses can be mirrors, opaque black, or even crystal balls! No, they're not heavy, they just look heavy. See the selection at S. Anomalous Etsy shop. Link
Moknuckles?
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