The very first comic Erik has ever worked on for Marvel Comics was The Mighty Thor #385.  He was basically just filling in for ol' Jack Kirby, and he filled them shoes mighty fine.  It was a pretty good issue, even with the primitive coloring and harsh inks.  Further down is also Erik's second run on the book with issues 26 through 28 in the new Mighty Thor series.  Erik was filling in for fan fave John Romita Jr with these issues, and the art was just great.  Check them out by clicking on the covers below...
 
 
 

LARSEN FACTS FOR THOR #385 *  Erik's name is spelled wrong on the inside credits (it's spelled "Eric").  *  This issue was a filler issue during Jack Kirby's run.  In Larsen's own words, "...was just filling in for ole' Jack there."  *  Erik reused a scene that appeared in this issue in Savage Dragon #34.  The scene is of a character throwing a train onto their opponent.  *  This issue was Erik Larsen's first work for Marvel Comics.  *  The art isn't usual Larsen fare, it's modified a bit so that it runs more in tune with Jack Kirby's art.  Larsen is a chameleon when it comes to art styles, he perfectly tunes his style so that it meshes with others, without swiping or blatant copying from said artist.  Very few artists can pull this off, and Erik is one of them.

Here's the cover pencils to Thor #27.  Larsen's run starts on Thor #26, but that cover will be done by MIKE MIGNOLA.  This is the first Larsen drawn cover of the run.  To view a larger version, click on the image at the left.