How would you code a weeping angel model?

Yeah. How would you code a weeping angel model so that it starts moving towards you when you arent looking at it.. I have tried in th past to make one. But failed at it.. I have thought that maybe you would use "WorldToScreenPoint()" or raycasting. Or the dot product. But i'm not sure?. Heres an old video from 2011 showcasing what i mean: https://www.youtube.com/watch?v=IGwD8KyHO6E

here's a free model that i found https://www.roblox.com/library/123576983/