donfos found a gif file. It looks suspicious. He told you to get the flag quickly and save him.
Can you get the flag for him?
Download file from : https://accessd.sfo2.digitaloceanspaces.com/foren200.gif
The file is a GIF image which shows several frames containg parts of the final flag.
The GIF must be split (e.g. using https://ezgif.com/split).
Using this online service you can easely remove the white background. Each frame must be merged in the same final image.
The merge operation can be performed via script or using an image manipulation program (MS Paint can be fine, but I used Adobe Illustrator).
Hence, the flag is: