The San Fransokyo graffiti pays homage to the Disney short 'Feast,' which plays ahead of 'Big Hero 6.' "Φst" incorporates the Greek letter phi (Φ) combined with "st," which gives you "feast" — sort of.
I also distinctly saw the cat dressed up as stitch in a pic on the wall during the one of the scenes that Hiro was on the stairs talking to his Aunt. Ill see if i can find a pic.
BIG HERO 6 - New TV Spots (2014) Disney Animation Movie HD
Big Hero 6 eased 38 percent to $34.7 million. That drop is a bit steeper than Wreck-It Ralph's 33 percent, and is roughly on par with Megamind's 37 percent. The Disney Animation hit has now earned $110.3 million; if it holds up decently against the one-two punch of Mockingjay and Penguins of Madagascar, it could eventually get to $200 million.