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Thank you very much @gidlark 🙂

That was a speed snail ;) lol ... no, I'm only joking ;)
As you know I have made 6 photos one after the other. There have been 1 or 2 seconds between the shots. The last one eas even a bit later.
Then I just opened these photos as layers in photoshop, aligned them and exported an animated GIF, that's all.
In reality you couldn't see the moves of this snail because it was really slow ;)

Shots with a difference of 2 seconds seem to be not long. I met the snails a long time ago, and when I met, it was mostly in the hiding place, so it is very difficult for me to estimate their real speed and how much time it takes to spend on such a gif. Thanks for the answer.

OK, then is was a speed snail ;)
I have just had a look at the Image data and you are completely right - there have been more seconds between, but honestly I thought it was shorter.