Bacteria/Molds

Hmmm. Sounds sinister. Any UFO activity in Tamworth of late?

Some time ago I noticed a roughly circular mark on my double glazed front door. The edges were irregular, several 'feet' protruding around the edge, similar to an amoeba, but not so big, and fairly regular. I didn't take much notice, thinking it was a mark left by a child calling for one of my children. Then my son noticed it was getting bigger. I measured it as having a diameter of approximately 66mm. It has now grown to about 85mm over the space of about a week. On examining it, it appears to be in the sealed gap between the two pieces of glass. I can only guess that it is a bacterium or mold of some sort, but my son and I would like to know. (I like to encourage this kind of investigation in my children, in the hopes it might spark a thirst for knowledge.) Can anybody give us some ideas as to what it might be, and what it is living on? Or point me to a place I might get some information.

Condensation is forming between the glass pieces and the mold is thriving off the wood. My best guess.

What colour(s)? If it's mold it should have some fuzziness to it. Does it? If it's between two panes of glass I would imagine it must be somewhat anaerobic.

It's hard to say what it is based on only a size description and having protruding feet!