What Happened

[Rexasaurous]

Please explain what this is?

 

[Determinate]

Press ' (key above TAB, and below ESC) on your keyboard and it will go away.

It's the new dev console available to all players.

 

[0 w n t z]

New Console....Prob pressed a button to bring it up...

 

[Red Widow]

It's a Console which Jagex has released for players use, basically if you're getting java errors you can find out what it is and fix it easier.

 

[Rexasaurous]

Thanks guys. =)