From the Puscifer facebook page:

“MAYNARD JAMES KEENAN GIVES SAMMY HAGAR THE WHEEL

In an effort to nudge the things forward in what seems to be an endless music writing process, Maynard James Keenan has enlisted the help of Sammy Hagar to temporarily replace him as the vocalist for the slow moving internationally recognized rock monster truck, Tool. “There seems to be this invisible speed limit we’ve been holding ourselves to. I believe Sammy can help us get all pistons firing and break some sound barriers.” Keenan went on to say, “Sammy is the only vocalist I’m aware of that was able to take an already established Van Halen an even greater distance. Hopefully this shift will help speed things along.”

https://www.facebook.com/PusciferMusic/photos/a.274814569494.143421.5930509494/10154700098729495/?type=3