Damian Wayne revealed!

Pets

It's a well-known and believed fact among the Batfamily that Damian adopts animals like Bruce does stray children.
They have yet to test and find out if it is a hereditary disease, curse or something else...

And, like them -not that they want to further acknowledge it-, Damian's animals are very diverse. From normal household pets like cats and dogs to farm animals like a turkey and cow to a literal fantasy dragon!

Still, he's tamed them all, and they listen to him. Something Bruce can't argue for himself. To be fair, he's certain his kids are too chaotic for even Darkseid to handle them all at once.

Anyways, Damian's pets also knew who they should treat with respect unless he said so or hinted at whom he disliked.
This caused them to -at some point- develop the opinion that they should help those he works with, especially when their in trouble.

Did he mention that he actually has even more animals?? Some that are even weider than a cow?

Instances of how Damian's pets cause headaches and came to the rescue:

The Young Justice and Justice League teams got trapped in another dimension; nothing new considering their occupational hazard. This is just a regular tuesday for them, pardon one exception. A giant -like skyscraper huge- black wolf with three pairs of eyes and chains was approaching them.

The beast recognizes Nightwing and Batman according to his masters one-sided talks and his smell lingering on them. His scent without Blood. Friendly.

Controversially, the sentiment isn't shared as they don't recognize the large canine, (never having been introduced because he didn't fit into the Batcave) and thus a fight breaks out. That is, until they see that he has a collar with the Robin emblem on it. Upon closer inspection by Superman, there was the name 'Nosyarg' in blood-red under it and a message on the back that said:

[Owned by the Son of Batman. Attack if you wish, but your spine and head will be mine.]

"..."

"..."

Tim rolled his eyes.

"..."

"..."

"..."

Bruce felt a headache incoming.

"..."

"..."

"..."

"..."

Dick stared, now in a new light of circumstances, enraptured by the sight of the quite magnificent beast who somehow seems to be even more invulnerable than Clark.

"..."

"..."

"..."

"..."

"...that is one of Damian's pets isn't it?" He continued.

"Oh, definitely" Tim punctuated.

"But how even?" Dick asked.

"Does this mean the brat was here before??" Tim considered.
Dick gave him a scolding look for being rude and insulting their brother.

By now the others were not so subtly eavesdropping their not so quiet, nevermind private, conversation.

"I've never heard of anything like this" Bruce said to them, looking at the large canine, that was looking a little wary after they had attacked it, before he brought his present protégés attention onto another issue: "I'm more concerned over the fact that he has most likely more hidden pets roaming around somewhere." He sighed, the idea sounding all too possible and, while he would follow through on questioning his youngest, he was dreading that particular answer.