Is this a virus on my macbook?
I was browsing a website and a popup came up that said ALERT (it was likely a fake apple or virus alert). Then all of a sudden a bunch of safari logos popped up at the bottom left corner of my screen and started moving up towards my download cursor at the top right side of safari, and hundreds of files starting being downloaded... The files are titled "Unknown," and close to 600 ended up being downloaded in my folder. It was very strange especially because a graphic had appeared at the bottom of my screen, of several safari logos being thrown up into my download folder. I will try and delete all the unknown files, but is this a virus and is my computer safe from trojans? What else should I do? I'm sorry if I haven't explained myself well, but I will attach some pictures to help anyone who needs more explanation... You can see in the pictures the ALERT tab which cause this, and then the unknown files being filled in my download folder.
MacBook Pro with Retina display, OS X Yosemite (10.10.5)