Other mistake: When showing "In Association with" in the English dub's credits, The Pokémon Company is misspelled as "The Pokeman Company." (01:15:37)
Continuity mistake: After the Pokémon are blown away, the front of Ash's hat changes from white to red. (00:46:03)
Continuity mistake: In the shot where they first visit the Lake of Life, Sam wades into the water (all the way up to his waist). As he steps out, there is only water at his ankles, and moments later, there is no water. (00:34:56)
Continuity mistake: When Ash says, "Hey, it's a kid," Sam has his right foot over his left one, but in the next shot, it is on the ground. Also, Brock's left foot is on stone, but in the next shot, it is on moss. (00:19:22)
Continuity mistake: When Towa tells Ash and friends to stay where they are, the amount of space between each rung on a ladder is 15 centimetres, but in the next shot, it is 7.5 centimetres. (00:17:33)
Continuity mistake: When Ash says that his name is Ash and that he can be a Pokémon Trainer too, a house has an awning with six red strips and five white ones, but in the next shot, it has three of each type. Also, the awning's window has its interior framing coloured white, but in the next shot, it is brown. Additionally, the house's balcony goes past the window and has panes of glass, but in the next shot, it is between it and has no panes. (00:11:23)
Continuity mistake: When a woman watering her plants notices the match below, the left shutter is open less between shots. (00:12:09)
Other mistake: When Celebi first heads over to Sam, the lower two segments of Scyther's thorax mistakenly have their colours swapped backward three times. (00:06:22)
Continuity mistake: When Sam thanks Towa for her gift, the rock to the right of Towa and the tree to the left of it are there, but in the next shot, they disappear. (00:04:30)
Continuity mistake: When the Iron-Masked Marauder hears that the man he has will tell him where Celebi is, the man's left hand changes position in accordance to the Iron-Masked Marauder's left leg. (00:09:59)
Continuity mistake: When Sam asks, "Time travel?" Towa's necklace is not on a violet part of her robe, but in the next shot, it is. (00:03:52)
Continuity mistake: When first showing the parting gift, Towa's left thumb is in between the top and the bottom of it, but in the next shot, it is at the top. (00:04:21)
Continuity mistake: In the recap of the shot where Ash puts on his right glove, he puts it on differently in the movie than in the episode where this takes place. Also, the shot on the television set is an upward-looking corner view, but in the episode, it is a straight-looking side view. Additionally, Gengar is moving, but it was not in the episode. Furthermore, the controls for the volume and another one do have symbols, but in the episode, they did not. Moreover, a curtain is draped over the right side of a window with Ash not having it behind him, but in the episode, the curtain was not draped over there with Ash having it behind him. (00:01:34)
Continuity mistake: When Towa says that Sam should not tell anyone about the Voice of the Forest if he hears about it, her right hand is on her apron, but in the next shot, it is on her robe. Also, the rock closest to the front of her has no crossing of ropes in front of her, but in the next shot, it has one. (00:03:41)
Continuity mistake: When Sam says that he has never heard about the Voice of the Forest, Towa's necklace is on a violet part of her robe, but in the next shot, it is not. (00:03:47)
Continuity mistake: When Sam is amazed by the power of time travel, the trees behind him change between shots. (00:03:59)
Revealing mistake: In the shot where Celebi calls for help, its shadow disappears before it leaves the screen. (00:05:28)
Continuity mistake: In the recap, in Pikachu's Poké Ball's receiving, the tiles are larger in the movie than in the episode. (00:01:53)
Answer: Missingno is a glitch from the video games, and is not a real pokemon, so no.
MasterOfAll