Only one in the world?? 0_o

Well basically my friend showed me these pics because he didnt know what the problem was with his plant. I tried to help him, but i cant find anyone that has the EXACT same problem. Might look like Mg deficiency or even spidermites, i DONT KNOW...

What it looks like when it starts: http://gyazo.com/7921437781d9ab5e53c5d94714ba371a

How it develops: http://gyazo.com/a9d42a4ed9152c20cafdf9821875949a

How it is at the most advanced place on the plant so far: http://gyazo.com/83bb73f0d82297b6db7b3840d600fd7e

Btw, hes at 3 weeks of flowering i think, not completely sure.

did you check for bugs?

Absolutely cant see shit, no apparent bugs, but i dont have a magnifying glass so.. cant be sure for the really small fuckers

might be calcium def