Random websites popping up on Safari, help?

Every time I type on the search and I click on a website, another one randomly pops up. It's anything. From stores to blogs. But it just does it every single time.

If I type for example: How to tie your shoelace and the results come out. When I click on any of them, a separate window pops up. Is this a Trojan Horse or something? If so, any safe programs to remove it? Would really appreciate the help. This is on Apple Safari.