Glad you enjoyed playing Moonlight Fortress! Thank you for your feedback!
I think I have an idea about what could have happened... I added a shortcut to unlock Pushkin to make it easier for my lecturer to see all the game's content without having to play for a long time. If you press "P", it will spawn Pushkin. It might be possible that you unintentionally pressed "P" so this is why he randomly turned up.