By the lion's mane
"Okay, this stuff prickles too." Mario pauses a moment to rinse his fingertips with water from his canteen. "I guess that means whatever feeds the lion fountain isn't the regular water we get from fountains and wells in the city."
While close by, he examines the wall the lion's head is mounted on, looking for mismatches, cracks, anything that might suggest a concealed door or trigger.