#2 Jonathan Woodgate
Debuts don't get any worse than that of Jonathan Woodgate, the stellar centre-back of Leeds United and Newcastle United signed by Real Madrid in 2004 for £13.4 million.
After spending the entire year on the sidelines due to an injury, his first match as a Galactico at the start of the 2005-06 season saw Woodgate score an own goal against Athletic Bilbao and then get sent off in that game.
It set the tone for the rest of his time in the Spanish capital. Woodgate was nowhere near his formidable self who took the Premier League by storm as he struggled to adapt to a new league and had a stinker everytime he took to the field.
With only 14 appearances throughout the campaign, Woodgate left for his hometown club Middlesbrough in 2006 but struggled with injury issues for the rest of his career.
#1 Kaka
When Real Madrid launched their 'Galactico 2.0' project in 2009 with a spate of big-money signings, the prospect of watching Cristiano Ronaldo and Kaka, the last two Ballon d'Or winners at the time, together was a tantalising one.
While the Portuguese went on to create history over the next decade, his Brazilian ally crashed and burned. Recurring injuries and poor on-field form plagued Kaka's time at Real Madrid as he made 120 appearances in four years and scored just 29 goals.
For someone who lifted the FIFA World Cup, the Champions League, the Serie A and was a Ballon d'Or and World Player of the Year award winner, it was a dramatic fall from grace as even a return to AC Milan in 2013 failed to reignite his career.