Complex sentence: A test pilot is missing and a search party is sent out in the jungles of Mexico; however, while searching they uncover a monster in the jungle who became this way due to a dose of radioactivity.
Split into simpler sentences: A test pilot is missing and a search party is sent out in the jungles of Mexico. However, while searching the area, they uncover a monster in the jungle who became this way due to a dose of radioactivity.