Looks like Dota 6.66b has a serious loophole which can cause a Fatal Error abuse. With certain steps, you can make all the player got a Fatal Error on their PCs.
Moreover, the recently released Warcraft 1.24e Patch also don't fix this problem. People are using this bug as an escape mechanism from losing a game.
If this is done right, all the people playing got Fatal Error and mostly the match will be restarted.
Of course this is not working on tournament that save the game every certain time. However, if you're on upper hand of a game and yet you got a Fatal Error, you must beware of this method.
How to Make Fatal Error Bug
1. Buy a Courier and use it.
2. Buy a Crow recipe and give it to the Courier.
3. Buy Ring of Protection then drop it.
4. Buy Sobi Mask then drop it a bit far from the Ring of Protection.
5. Use the Shift button/queue command on the Courier to make him pick the Ring of Protection then the Sobi Mask then transform to Crow. (place your Courier a bit far from those items, hold Shift and then right click on the Ring of Protection, right click on the Sobi Mask and left click on the change into Crow button, release Shift)
6. To know if it is successful, the Courier will turn into Crow but the Ring of Basilius is not formed.
7. Build Armlet of Mordiggian, activate it then give it to the Crow.
8. Last step, once the Armlet of Mordiggian already on the Crow, click it and BOOM.. Fatal error will occur to all the players at the game.