ABSOLUTELY NOTHING ... 'cause this is the most freakin' adorable thing you'll ever see!!!

The Blues adopted a Labrador Retriever just a few weeks ago ... and they finally let him hit the ice with the squad Thursday -- and the ensuing cuteness was uncontrollable.

The pup -- named Barclay, or Barc for short -- showed off his speed AND his stick-handling skills ... all while his ears flopped in the chill and his big paws tore up the ice.

LOOK AT HIM!!!!!!!

The Blues have big plans for the pup -- who was named after legendary Blues defenseman Barclay Plager -- 'cause the squad says they're going to train him to be a future assistance dog.

In the meantime ... he'll forever remain the cutest member of the Blues.

Eat your heart out, Alex Pietrangelo.