Market makers shorting to fill buy orders - Is this an essential mechanism to ensure timely trades or artificial transactions disrupting price discovery and supply/demand economics? Are there any other fun market maker mechanisms that you aware of?

I’ve always been curious about the mechanics of market making and the mechanisms for filling orders. I’m not sure if shorting shares to fill orders is even a common practice - just curious on everyone’s perspective. Seems like a necessary evil but leaves the market vulnerable to manipulation. Does anyone have any fun insight?