the card game

If any defensive play on an inside-the-park home run is labeled an error by the official scorer, a home run is not scored; instead, it is scored as a single, double, etc., and the batter-runner and any applicable preceding runners are said to have taken all additional bases on error. All runs scored on such a play, however, still count.

An example of an unexpected bounce occurred during the 2007 Major League Baseball All-Star Game at AT&T Park in San Francisco on July 10, 2007. Ichiro Suzuki of the American League team hit a fly ball off the right-center field wall, which caromed in the opposite direction from where National League right fielder Ken Griffey, Jr. was expecting it to go. By the time the ball was relayed, Ichiro had already crossed the plate standing up. This was the first inside-the-park home run in All-Star Game history, and led to Suzuki being named the game's Most Valuable Player.
Specific situation home runs

These types of home runs are characterized by the specific game situation in which they occur, and can theoretically occur on either an outside-the-park or inside-the-park home run.
Grand slam
Main article: Grand slam (baseball)

Home runs are often characterized by the number of runners on base at the time, if any. A home run hit with the bases empty is seldom called a "one-run homer", but rather a "solo" homer. With one or two runners on base, the home runs are usually called "two-run homers" or "three-run homers". The term "four-run homer" is seldom used. Instead, it is nearly always called a "grand slam".

A grand slam occurs when the bases are "loaded" (that is, there are base runners standing at first, second, and third base) and the batter hits a home run. According to The Dickson Baseball Dictionary, the term originated in the card game of contract bridge. An inside-the-park grand slam is a grand slam without the ball leaving the field, and it is very rare, due to the relative rarity of loading the bases along with the significant rarity (nowadays) of inside-the-park home runs.

On July 25, 1956 Roberto Clemente became the only MLB player to have ever scored a walk-off inside-the-park grand slam in a 9–8 Pittsburgh Pirates win over the Chicago Cubs, at Forbes Field.

On April 23, 1999, Fernando Tatís made history by hitting two grand slams in one inning, both against Chan Ho Park of the Los Angeles Dodgers. With this feat, Tatís also set a Major-League record with 8 RBI in one inning.

On July 29, 2003 against the Texas Rangers, Bill Mueller of the Boston Red Sox became the only player in major league history to hit two grand slams in one game from opposite sides of the plate. In fact, he hit three home runs in that game, and his two grand slams were in consecutive at-bats.