It's a promo card for the second movie, which was named "Maboroshi no Pokemon Lugia Bakutan" in Japanese. "Bakutan" technically literally means "explosive birth", but "birth" here should be interpreted more liberally as "appearance", "debut" etc.
The "baku" prefix is just one of those common prefixes tossed onto words to make them sound more extreme or impressive, the literal meaning is pretty irrelevant.
Writer Takeshi Shudo fucking hated this title for the record, since the word "bakutan" has absolutely nothing to do with the content of the movie and was clearly just put there by the marketers to sound cool.
