Sam Clucas was our one-time record fee for Swansea and cost a ridiculous £15 million after selling Gylfi for £40 million. The fee wasn't his fault but he was just one of many bad performers in our final Premier League season, so fans bollocked him. Single season, sold, and now regularly scores against Swansea - celebrating like Adebayor against Arsenal on one occasion.
Roque Mesa cost £11 million for 11 games. Borja Baston was signed for £15 million and scored one Premier League goal, got loaned out a bunch of times and scored a handful in the Championship before leaving on a January free.
Then there's a string of one season wonders like Jose Moreira, Franck Tabanou, David N'Gog, Eder and Itay Shechter.