Steam has now removed suspicious mods of the popular game Cities: Skylines after users complained of performance regressions upon installing a redesigned Harmony mod. Turns out that the redesigned mod was created by a notorious developer named Chaos, who put users' computers at serious risk of getting infected by trojans, keyloggers, and Bitcoin miners.
https://www.notebookcheck.net/Potential-malware-ridden-Bitcoin-mining-Cities-Skylines-mods-removed-by-Steam.601257.0.html