Unknown visitor

OMG I just realized there has been some unknown visitor into our room for a couple of time now!!! And today something just confirmed it!!! EVIDENCE OF OUR ROOM INTRUSION==>

its SMALL FOOT!!!
Its not distinct when taken as a pic, but it was damn clear what THOSE footprints show. Well I had my suspicion b4 this episode...but it also involved a footprint...not on the floor, but even more obvious, well duh coz that UNKNOWN visitor made its mark ON MY NEW CLEAN AND WHITE LAB COAT!!! *ROARRR* But back then, it was just one mark, so i thought maybe I got it from outside?? [don't know how i came to that conclusion, seeing back now how absurb that seemed]
And somehow I have a strong feeling that this unknown visitor has been visiting Us at night?!? EEEKKKK~! well, so far i still got 10 fingers, and 10 toes, so i take it as this visitor is not interested in human meat..phew. And also no food went missing..not that we leave any open [unless our visitor here knows how to cook instant noodles la]
Nevertherless, this still concerns me as since this visitor can come in to god knows do what, I wouldn't want our dear visitor to leave a " visiting gift". SO far its been footprints...next time who knows? I might wake up to "chocolate cake"on my face or step on it when i get down from my bed....Not a great way to start my day.
Or what if our visitor decides that he/she likes to visit us and next time brings along their families?! Gosh, that would be unimaginable....
Not to mention the thought what the unknown visitor did when he/she visits us at night while we were in La la Land.... Ugh okay, no more open windows at night...
Below is a more obvious picture...since i edited it.

NOW ITS CLEAR!!!