More than a dozen apps have been highlighted by a malware analyst because they have been infected by the notorious Joker software. Installing Joker can lead the user to being subscribed to services they do not require, incurring a loss of income. One of the infected apps, EmojiOneKeyboard, has already registered over 50,000 installs.
https://www.notebookcheck.net/Joker-malware-discovered-in-multiple-apps-with-thousands-of-installs-on-the-Google-Play-Store.581012.0.html