## Kotlin, <strike>67</strike> 66 bytes ##
<!-- language: kotlin -->

    while(1>0)"|/-\\".map{print("\rLoading... $it");Thread.sleep(250)}

[![enter image description here][1]][1]

Fairly self explanatory, using `\r` to clear the line and taking advantage of Kotlin's awesome string interpolation.

EDIT: Saved 1 byte thanks to @mEQ5aNLrK3lqs3kfSa5HbvsTWe0nIu by changing `while(true)` to `while(1>0)`


  [1]: https://i.stack.imgur.com/FdSsE.gif