How was Elon Musk involved in Paypal?

Context: Individuals whom the media refers to as members of the PayPal Mafia include:

Peter Thiel, PayPal founder and former chief executive officer who is sometimes referred to as the "don" of the PayPal Mafia
Max Levchin, founder and chief technology officer at PayPal
Elon Musk, co-founder of Zip2, founder of X.com which merged with Confinity to form PayPal. Musk later founded SpaceX, co-founded Tesla, Inc., co-founded OpenAI, Neuralink, founded The Boring Company, and became owner of Twitter, Inc.
David O. Sacks, former PayPal COO who later founded Geni.com and Yammer
Scott Banister, early advisor and board member at PayPal.
Roelof Botha, former PayPal CFO who later became a partner and Senior Steward of venture capital firm Sequoia Capital
Steve Chen, former PayPal engineer who co-founded YouTube.
Reid Hoffman, former executive vice president who later founded LinkedIn and was an early investor in Facebook, Aviary
Ken Howery, former PayPal CFO who became a partner at Founders Fund
Chad Hurley, former PayPal web designer who co-founded YouTube
Eric M. Jackson, who wrote the book The PayPal Wars and became chief executive officer of WND Books and co-founded CapLinked
Jawed Karim, former PayPal engineer who co-founded YouTube
Jared Kopf, former PayPal who co-founded Slide, HomeRun and NextRoll
Dave McClure, former PayPal marketing director, a super angel investor for start up companies
Andrew McCormack, co-founder of Valar Ventures
Luke Nosek, PayPal co-founder and former vice president of marketing and strategy, became a partner at Founders Fund with Peter Thiel and Ken Howery
Keith Rabois, former executive at PayPal who later worked at LinkedIn, Slide, Square, Khosla Ventures, and currently with Peter Thiel at Founders Fund, and personally invested in Tokbox, Xoom, Slide, LinkedIn, Geni, Room 9 Entertainment, YouTube, and Yelp
Jack Selby, former vice president of corporate and international development at PayPal who co-founded Clarium Capital with Peter Thiel, later becoming managing director of Grandmaster Capital Management
Premal Shah, former product manager at PayPal, became the founding president of Kiva.org
Russel Simmons, former PayPal engineer who co-founded Yelp Inc.
Jeremy Stoppelman, former vice president of technology at PayPal who later co-founded Yelp
Yishan Wong, former engineering manager at PayPal, later worked at Facebook and became the CEO of Reddit

Answer: Elon Musk founded X.com, which merged with Confinity to form Paypal.