This is the personalised version of E.
Nesbit’s Five Children & It.
Sophie
and Serena go on holiday and decide to dig a hole to Australia. In doing so,
they meet a very strange creature with eyes on stalks and feet like a monkey
who calls himself a Psammead and claims to be able to give wishes. This turns
out to be true…but whoever said you should be careful what you wish for
couldn’t have been more right.