I first came across the ontological argument (in the form of Anselm) in Religious Studies class when I was 16, and my immediate reaction was, "that's a load of bollocks". However, I was assured repeatedly that all sorts of clever people were impressed by it - even when I went on to study philosophy at university, lecturers were informing me there's more to the argument if you don't look at it superficially. Theists loved trotting out that old story about David Hume walking down the street and proclaiming in shock that the ontological argument is sound!
So, with all this encouragement, I read more, and thought about the arguments for several years. Eventually, I came to the realisation that I had nailed it as a 16-year-old, and for exactly the same reasons.
The Googlesplat is defined as a giant, pink fire-breathing unicorn that necessarily exists.
The Googlesplat exists by definition.
Nevertheless, the Googlesplat does not, in fact, exist.
This is all that's necessary to see why ontological arguments are steaming piles of horseshit, and all the reams of text written to justify them is simply empty hand-waving. Don't be too hard on philosophers in general though - ever since Anselm's day plenty of professional philosophers have laughed derisively at such nonsense.