Sherlock: 20 Easter Eggs, In-Jokes And References
9. Redbeard
During a visit to Sherlocks mind palace in His Last Vow, we see Sherlocks childhood dog Redbeard. We learn how little Sherlock was heartbroken when Redbeard was put down a fascinating hint at how different he was as a child.
This is also something of a double-edged easter egg (if that makes sense). Firstly, it might well be a nod to Citizen Kane, in which Charles Foster Kanes lost innocence is symbolised by his childhood sled Rosebud. The two scenarios and names, actually - are somewhat similar.
It is also a reference to an earlier clue about Sherlocks childhood. In A Scandal In Belgravia, Mycroft tells John how Sherlock wanted to be a pirate when he was a boy. Naturally, little pirate-obsessed Sherlock would name his dog after the famous buccaneer Redbeard.