If you doubt Unicorns exist then you'll have no choice, you'll have to explain to your children that they don't exist or just comfort their disappointment when they can't find one.
To help comfort the disappointment you can either dress up as a horse and paint yourself white or get one of these Inflatable Unicorns.
The Inflatable Unicorn is probably just about as big as a supposed real Unicorn, but as this inflatable one is quite big we will assume that this is a Giant Inflatable Unicorn, that may or may not have supernatural powers that creates rainbows from its bum as it flies.
The Inflatable Unicorn has a rainbow tail and rainbow mane, just like the real ones.
Inflate with care - do not use for flying.
The Giant Inflatable Unicorn is 7ft high (size Large), that includes the horn.
The Small Inflatable Unicorn, though called small is also quite large standing at 40" tall