Beware of the Babysitter(1999)
(The fourth book in the Blobheads series)
A Chapter Book by Chris Riddell and Paul Stewart
The most High Emperor of the Universe (Billy's baby brother, Silas) is in great danger. The Blobheads must protect him from the wickedest monster in all creation - a huge creature with twenty-six arms, eight glowing eyes and vile breath, known only as Sandra. And Sandra is a master of disguise.
Used availability for Chris Riddell's Beware of the Babysitter
December 1999 : USA Paperback
April 2000 : UK Paperback