An old post type I tried to delete shows up like a tag on my website...how can I truly remove it?

I had an old post type called "videos," which strangely appeared under all my posts like a tag, with the same button that all my tags have. Clicking it would lead to a URL ending in type/video that contained all of my posts. I don't actually need that post type anymore, and so I deleted it, but the strange tag-imitating button remains. Any tips on how to go about really getting rid of it?