My "applications" folder in the dock has gone rogue

Hi, first post, thanks in advance for any help offered.

My "applications" folder in the dock has been doing strange things. At first it changed to a crossed out circle icon. Then after downloading some mp3s from amazon it has changed to an amazon music icon.

I have tried changing it by ctrl/click, get info, select icon, pasting in a new image. The new image is visible in the finder but when you close the finder the icon on the desktop hasn't changed.

Any ideas?

See attached screenshots.

 

Aha! Solved. My dumb. Thanks BrianBaughn, seasons greetings to you sir.