Unusual arrow at the bottom of mySafari icon on my doc

It is an Alias arrow.

When you drag an application icon from the Application folder to the Desktop, an alias icon is placed on the Desktop.

If you drag that alias icon to the Dock, that adds an alias icon to the Dock.

To remove it, right click on the icon.

When the contextual menu pops up, choose "Options' and then "Remove from Dock".

That little black arrow means you have Safari open. It's normal.

When you quit Safari, the black arrow will vanish.

That way you can look at your Dock and see exactly which apps are running.

Good catch dominic23 !!