One of the Industry On Parade shows that I keep in my bedtime playlist features the Scripto Liquid Lead pencil. (Around the 5 minute mark.) Basically a ballpoint pen with graphite ink.
The film shows fine details of the manufacturing process, which was fascinating. The product seemed unlikely to succeed, and in fact it didn’t. Like a flying car, it mixes two goals that are already satisfied by separate products. People who write with pens want an indelible mark. People who write with pencils enjoy the feeling of sliding the graphite across the paper. Each has a distinct purpose and a distinct sensory pleasure. There’s no such thing as an average of two separate ideas or two separate pleasures.
This webpage tells the later history. It sold well for a year, then dropped quickly as people spent time with it and lost the novelty.
Polistra's Mill 