Shifter waved to Selia when Robin introduced him, and he wanted to do something fun since the heroes were busy saving the world once again. This whole fire thing at Cadmus sounded interesting and Walt was willing to check it out. When Robin and Selia began to talk about cliches, Walt laughed and changed into Sylvester the Looney Tune character. 

"if striking poses is consider cliche then I will be absolutely despicable" he said trying to imitate the speech pattern of the cartoon cat. he changed back to normal and then put his hand in the center with his two new friends.

"So are we heading to Cadmus now or do we get lunch first?" Walt asked and cracked up laughing.