Yes, there is a Captain Underpants 11. The eleventh book in the series is titled "Captain Underpants and the Tyrannical Retaliation of the Turbo Toilet 2000" and was released on August 26th, 2014. The book is written and illustrated by Dav Pilkey, the creator of the Captain Underpants series.
In "Captain Underpants and the Tyrannical Retaliation of the Turbo Toilet 2000," George Beard and Harold Hutchins find themselves in trouble once again. To make matters worse, their beloved Principal Krupp has been replaced with an evil doppelganger. This new principal, Mr. Meaner, is on a mission to rid the school of fun and laughter, including the popular comic book club that George and Harold belong to.
In an effort to stop Mr. Meaner and save their school, George and Harold create a giant robot version of their infamous creation, the Turbo Toilet 2000. However, things quickly spiral out of control, and the Turbo Toilet 2000 becomes a raging menace, wreaking havoc on the school and its inhabitants.
As always, Captain Underpants comes to the rescue, battling against the Turbo Toilet and Mr. Meaner in his classic style. Along the way, readers can expect plenty of humor and hijinks, as well as Pilkey's trademark creative illustrations and storytelling.
Overall, "Captain Underpants and the Tyrannical Retaliation of the Turbo Toilet 2000" is another exciting and entertaining addition to the series. Fans of the previous books will delight in the new adventures and shenanigans of George, Harold, and Captain Underpants.