So Caribou has information on both ancient weapons: Pluton is in Wano, and Shirihoushi is Poseidon. A common theory I see is that Caribou is talking about giving that information to Blackbeard. But what if he actually means Crocodile? All Crocodile wanted out of Alabasta was to know about Pluton, now someone comes forward who knows where it AND Poseidon are? And all of a sudden Crocodile is reintroduced into the story alongside a Yonko WHO VERY MUCH WOULD like to use the ancient weapons (unlike Luffy)? Buggy failing upwards into possession of ancient weapons would be hilarious.