Giant moving mud puddle tries to take out a TRAIN

Yeah I really don't think that this mud puddle is moving at all. I think that this area has a vast amount of geothermal caverns who's activity consistently switches from cavern to cavern to cavern and giving the perception as if it's a single moving entity when it's not. 

No of course I could be wrong However I tend to execute Occam's razor throughout my daily life and that makes the most sense in my opinion.