How does one see something that wouldn't normally be seen but can be seen anyway?

There's a lot of possible answers. For example, something moving extremely fast can't be seen to the naked eye but can ne seen when slowed down. Or invisible gasses, like oxygen, can be seen when frozen or liquefied.
You should be more specific.

I meant bones. You can only see flesh normally, but with X-Ray vision, you see bones.

Well you were incredibly vague. Theres probably like, hundreds of possible answers if you got creative enough.

Back on-topic...
Say something that can't be heard but seen.

Nothing physical. An idea like love can be "seen", but not really. Even the most miniscule of atomic movements make noise.
I guess maybe a black hole? But that can't be seen, as light cannot escape it. And technically sound still exists within it, it just can't be heard. Light too. If you were to enter a black hole, you could "see" it. But not really.
anyway
What's the answer?

I was referring to the curse filters, lol. I'M NOT CREATIVE, OKAY?

"Which road do I take to get to your hometown?" Both point to Truthsville.

It bites without teeth, you can feel it but not see it. *cough*Hobbit*cough*

The cold.

I live with many others, and I never want to leave,
Though I fight with them for survival every day since the day I was born.

Some kind of bug, I feel. Spiders? Maybe some kind of fish?

Plants/a tree.

A tree. Right you are, sir.

The fight for the sunlight, eh?