Continuity mistake: When the Penguin goes to visit his parents grave, the umbrella he drops before he walks up to it changes position between shots, alternation from beside / in front of the bush. (00:39:10)
Continuity mistake: After Max Schrek throws some of the presents out to the crowd, when it cuts back, between shots a large green present on the top of the pile vanishes. (00:09:55)
Continuity mistake: When Max is talking to Bruce in his office, the pen and the tray with the coffee pot on it move closer between shots, as Max gets up from his chair. (00:43:00)
Continuity mistake: During shots, before the shot of the two cats coming through the window and onto the table, the items on the table (lamp, snowglobe, glowing santa, etc.) change positions. (00:30:15)
Continuity mistake: When Selina arrives back home after being pushed out the window, she presses her answering machine button and brings her arm to her side. In the next shot her hand is on the machine again. (00:29:05)
Continuity mistake: When the joker henchman busts the door and lifts up a flaming stick to blow at a pile of teddys, the angle in which he holds the stick differs through consecutive shots. (00:13:40)
Continuity mistake: When Max leads the Penguin over to the two image consultants, Josh, the male one, reaches back with his right hand for a cigar. In the next shot he's using his left hand. (00:48:45)
Continuity mistake: The yellow bottles of fish food jump from the radio to the fridge, from when Selina arrives home the first time, goes off back to work, then returns back home the second time. (00:22:30 - 00:28:50)
Continuity mistake: When Selina returns home from work a second time she takes milk out of the fridge and pours her cat some. She then starts to drink some, spilling it all down her neck and blouse. When it cuts though her neck and blouse are suddenly cleaned up. (00:29:00)
Continuity mistake: When the Penguin is first talking to Max, about him helping him emerge from the sewers, he spits as he speaks, and black spit covers his chin. The spit disappears when he begins to show Max the toxic waste, then reappears and vanishes again. (00:20:00)
Continuity mistake: Selina dumps her coat, scarf and bag on the sofa seat when she gets home. In another shot the coat and scarf have changed position, and the bag is gone. (00:22:30)
Continuity mistake: As Selina is about to make her cat suit, she grabs a pair of blue handled scissors, yet in the next shot they're pink. (00:31:05)
Continuity mistake: When the camera pans up to show the Schrek headquaters, in the first shot a warm blue light is coming from the windows, and no pillar lights are on. In an overhead shot bright light is on, and emitted. (00:07:00)
Continuity mistake: After the Penguin bites the male image consultants nose, he has no blood on his chin. In the next shot it is covered in blood. (00:49:45)
Continuity mistake: When Selina puts her soft toys into the sink, she grabs a wooden spoon and begins to stab a pink teddy down into the shredder. But in a closeup she is now pushing a soft toy monkey into the shredder. (00:29:45)
Continuity mistake: When Catwoman smashes a glass display case in Schrek's department store, the position of the items on and around the case change between shots. (00:54:25)
Continuity mistake: When the Penguin is controlling Batman's batmobile, when the batmobile hits a police car, the car flies into a '24 Hours' shop. Between shots the amount of hubcaps and tires hanging on the brick wall around the doorway of the '24 Hours' changes. (01:20:15)
Continuity mistake: When the Penguin pours Catwoman a glass of champagne, the properties of the bubbles and the actual amount of champagne in Catwoman's glass differs. (01:17:40)
Continuity mistake: The position of the cards and notices stuck on Seleia's fridge change, from when she gets the milk out of the fridge when she's normal, to when she goes back to the fridge later, after being pushed from the window. (00:22:30 - 00:28:55)
Continuity mistake: The location of The Penguin when he falls through the window and into the pool, changes. He moves much further away from the concrete platform. (01:45:50)
Answer: It isn't. If you look at when he dies you will see that he has cuts on his face that are bleeding red. The blue liquid is more like a bile, probably similar to saliva.