Tell me more about dad!Hal pretty please
Hal would fight Batman for custody rights of the many many Robins and sidekicks if he thought he could win in both a legal court and fist fight against the Bat. Doesn't stop him from becoming the favorite of each new sidekick. These kids need an emotionally available parent damn it!
Sadly he lost that battle for being Dick and Jason's favorite due to not being around alot as they were starting out, but he is rather smug he is the rest's favorite.
Though he shares being Steph's favorite with Barry and that's okay.
Hal doesn't know who started it...but one of the kids or his coworkers started calling him Mama Bear and it...stuck. No matter how much he protests that he is not the 'Mom' of Batman's brood.
Also it was Barry. Barry was the one who started it after Hal went off on a rant about Robin (Dick) almost getting hurt because Bats had brought Robin along to help with an Alien Invasion. Hal had spent the entire fight protecting the little Robin as he cackled and sprung around the battle field. Total Mama Bear
There is a lot of photographic evidence of Hal and Robin (each one of them) or other Batkid Sidekicks napping together in the Watch Tower. Some with Batman brooding protectively in a shadow as the two nap. Even some of Hal being swamped by former-Robins and other batkids in a puppy nap pile. They are adorable
One photo was used as the JLA Christmas card photo.