It's called a cursor.
It can become invisible if it's on the bottom or right edges of the screen. There are no other way for the cursor to disappear.
If for any reason your mouse or track pad don't work, it will stay there.
The mouse may be disconnected. If it's a wireless mouse, it may be turned OFF or it's battery may be discharged or the dongle that is needed to communicate may be disconnected.
Depending on your case:
Reconnect the mouse or dongle.
Turn the mouse ON.
Replace or recharge the battery in the mouse.
I have NO experience with track pads and can't help on that topic.
Electro, August 2016
