Immune: constructs, kami, ooze, plant, qlippoth, undead (usually), vermin; paladins of 3rd level or higher

A panicked creature must drop anything it holds and flee at top speed from the source of its fear, as well as any other dangers it encounters, along a random path. It can't take any other actions. In addition, the creature takes a –2 penalty on all saving throws, skill checks, and ability checks. If cornered, a panicked creature cowers and does not attack, typically using the total defense action in combat. A panicked creature can use special abilities, including spells, to flee; indeed, the creature must use such means if they are the only way to escape.

Panicked is a more extreme state of fear than shaken or frightened.

Marius, Scholai Armsmaster Says: There are two differences between the Panicked condition and the frightened condition.  First, a panicked creature drops what they are holding.  Second, a panicked creature will cower if cornered, while a frightened creature will keep trying to find a way to leave.