I see them on teams like Vancouver and Florida but I have no idea what it means

Players who signed contracts that are illegal now, and then retire, such as Luongo, Suter, Parise, Weber, Hossa, and more, teams now would have a penalty if they retire before the end of the contract

My explanation might not be the best but it’s a start

Like the 13 year contract or whatever that Crosby has?

I think this explains it well: https://www.google.ca/amp/s/amp.reddit.com/r/hockey/comments/3ctmu2/the_cap_recapture_penalty_what_it_is_and_why_it/

Under the former CBA, some GM's signed players to long term, front loaded contracts that circumvented the cap. If the player retires, the team that signed that contract is now on the hook for a percentage of that contract. I don't believe that any contracts signed under the current CBA could result in a RCP in a player retires early. For examples, see Roberto Luongo and Ilya Kovalchuk.

There's also a a Sporting News article that details VAN's RCP with Luongo that provides good context. But, it's a complicated issue.