Ferrofluids, yea it is new to me too

I am working on this project that needs magnets, magnets are cool we all know that. I plan to use rare earth magnets because they’re coolest, they are rare and earthy. So, I am out at a magnet supply site looking for a source and I see a menu option titled “Magnetic Tools-Films-Fluids & Gadgets”. Fluids, really….. What can you do with that, quite a bit it seems. Now all I need to do is figure out what I can do with that.