"They have hired people we've fired. We always jokingly call Apple the 'Tesla Graveyard'. If you don't make it at Tesla, you go work at Apple. I'm not kidding," Musk told German newspaper Handelsblatt, while touring Berlin.
When pushed on whether he took Apple's ambitions in the auto sector seriously, the billionaire's response was even more scathing, mocking the Cupertino, CA-based company's latest products.
"Did you ever take a look at the Apple Watch?," Musk said.
"No, seriously: It's good that Apple is moving and investing in this direction. But cars are very complex compared to phones or smartwatches. You can't just go to a supplier like Foxconn and say: Build me a car."
Apple was not immediately available for comment.
Speculation has been building all year that Apple is looking to develop its own electric car and jump into the auto sector. In July, Apple hired industry veteran Doug Betts, who led global quality at Fiat Chrysler Automobiles. And in August, "Project Titan" – the name for Apple's car project – got more credibility after reports that the firm was looking for an area to test the car in Silicon Valley.
As recently as last month, Apple executives met with officials from California's automotive sector to discuss self-driving vehicles.
An Apple car – whether it be electric or driverless – will compete directly with the likes of Tesla and the traditional carmakers from BMW to Mercedes.
Silicon Valley's biggest technology firms are also looking at the auto space. Google is currently testing its own vehicle while taxi app Uber poached researchers from Carnegie Mellon University to work on autonomous driving technology.
At the same time, traditional carmakers are looking to fend off the threat. Earlier this year, a conglomerate of German carmakers bought Nokia's HERE mapping system which is seen as a key component of autonomous driving.
Musk however admitted that a car would make sense for Apple.
"But for Apple, the car is the next logical thing to finally offer a significant innovation. A new pencil or a bigger iPad alone were not relevant enough," Musk said.