Will Self: PsychoGeography

"The villa," Marc remarks magniloquently, "is like something that might have been designed by the bastard offspring of Gianni Versace and Saddam Hussein." It's worse than pedantic to point out that this is a biological impossibility, because the villa definitely does look like precisely this; and if it can exist, then why not the love-architect of the dress designer and the dictator?

The villa is surmounted by a dome studded with enough stones for a thousand rockeries. The rooms are white and red with heavy wooden beams. The entrance hall – white marble floor, natch – is dominated by a Moorish fountain. There are ashtrays like chandeliers and chandeliers like ashtrays. There are silky sofas the colour of semiprecious stones in abundance. An enormous bull's head is nailed to a plaque high up on the kitchen wall; you might be tempted to slice carpaccio off it – if you were insane. The outbuildings are faux-adobe, the gardens are full of palms and Dr Seuss-style exercises in topiary. The pool points south, towards Ibiza town, where the bastion of the Crusader castle, topped by the 18th-century cathedral, dominates the skyline.

Everyone gets the villa they deserve, on this, the most mutable and hallucinogenic of isles. The lotus eaters slob out by the pool, cuddling with Circe, while I keep expecting a wealthy Mexican to thrust his dishonoured daughter in my face and order me to bring him the head of Alfredo Garcia. Meanwhile, Warren Oates crouches in the pool house, cooing to a bloody lump in a hessian sack. We eat lunch within a loggia, talking of ingesting MDMA rectally and the foibles of the Great Powers. Wasps swarm on the lumps of chicken and beef we've left for them, then, too obese to sting, they blade-hop back to their subterranean nest in the rockery by the pool.

When night falls, we leap into our Chrysler MPVs and race in convoy through the faux-adobe towns and the parched hillocks of the hinterland, to where temporary car park attendants wave torches, assigning Porsches and Ferraris to the dusty ditch. We debouch, and follow soused starlets, tottering like newborn foals on high-hoofs, into parties organised for friendless internet billionaires by unpopular retail millionaires. Barmen mix mojitos with all the time in the world, while you wait in a queue of haircare-product tycoons and Russian wives-by-the-hour. A man taps you on the shoulder: he once sold you a shirt, in Soho, in the last millennium.

Ah! Ibiza, with your infinity pools and your retiree dancers who're convinced they'll jig forever! Ah! Ibiza, with your congealed beaches and your foamy dance floors – who could not love you, such is your sybaritic honesty, your wilful disregard for any culture save club culture. The charter jets take off all through the dark night, their fuselages seamed by lighting over the Balearics, carrying gel-heads back to the K-holes of Manchester, Leeds and Birmingham! Who can fail to wax lyrical – or even just wax.

One afternoon my daughter and I scale the old town, penetrating the 60-foot-thick walls of the bastion. We stroll up through the narrow streets of the old medina, past cafés and tourist tat-shops. A Hassidic man stands on a balcony dressed in black, small leather boxes containing verses of a holy book are tied to his forehead and his upper arm, he rocks back and forth, sing-speaking his creed. He wouldn't look out of place in clubs like Privilege or DC9 – but what's he doing here?

Another morning, and suffering a tad from claustrophobia, I drive up to the north, in search of the wilder side of Ibiza. But if this is wild, Regent's Park is the Yukon. True, the hills are a little higher, and the villas are a bit more spaced out, but you still sense that behind every "Privado" sign there lurks a Milanese bra manufacturer with too much time on his hands.

My nine-year-old and I tramp along 4km of dusty blacktop, between drowsy olive groves. Finally, the road loops down through 5m-high stands of bamboo to a rocky inlet. At last, after the teeming streets of Eivissa and Sant Antoni, and the choked beaches of D'en Bossa and Benirass, there is no one; or rather, only a fat Frenchman, who squats naked beside some fishermen's huts – and that's as good as no one.

We disrobe and inch our way into the waters. True they aren't possessed of the deep clarity of the Prime Minister's political thinking – but nor are they brown. We splash for a few seconds, then we are both stung by jellyfish. Nursing our electrified limbs we retreat to the rocks, where the Frenchman lazily observes: "Thees side of the cove is, owewesai? Thees side is full of the medusas..."

But his warning is way too late, because once more that greater Gorgon – Ibiza – is in our sights: the snakes writhe above her D&G sunglasses, and we're turned ... to stone.