Scale degrees are regularly altered (modified), and it sounds like what it sounds like. Now you've heard what this particular modification sounds like, and you'll be able to use that sound in the future, when you want that sound.
An essential element in sheet music notation is accidentals which are used to show alterations to scale degrees. By notational convention, the alterations are temporary and are automatically cancelled at the next barline. This convention is because that's how pieces are usually built. Alterations are temporary, and when they are returned back to normal, that's a kind of a tension/release element.
I wrote a chord accompaniment harmonization for this melody.
To add further scale degree alterations, I made a change in the last bar, making the chord a proper dominant-seventh chord.
Try making more further modifications and listen to the new sounds. How about this one, do you like the sound?
Many of the scales obtained via these alterations have specific names, but I'm not sure if learning a lot of fancy names does more harm or good. The names don't matter, only the sound matters and that you know how the sound was made.