A rounded, solid wooden or hollow aluminum bat. Wooden bats are traditionally made from ash wood, though maple and bamboo is also sometimes used. Aluminum bats are not permitted in professional leagues, but are frequently used in amateur leagues. Composite bats are also available, essentially wooden bats with a metal rod inside. Bamboo bats are also becoming popular.
Maple bats in particular were once known (circa 2008) to potentially shatter in a way that resulted in many sharp edges, sometimes creating more dangerous projectiles when a bat broke.[9][13] Maple bat manufacture evolved significantly, in cooperation with Major League Baseball,[11] paying special attention to grain slope, and including an ink spot test to confirm safest wood grain orientation.[11]
A fungo bat is used by the coach to hit ground balls or fly balls to his team. All throughout high school and college many players use fungo bats to play fungo golf. This is when each person has a fungo bat and a baseball and they pick out targets around their field or complex and basically play it in the same manner as golf. Fungo bats should not be used to hit a pitched baseball because they are much weaker than normal bats and will break much much easier.
Even in those formative years, authorities on the game warned the practice of hitting fungoes should be limited to coaches. Henry Chadwick, one of baseball’s earliest proponents, claimed “The weakest batting is shown when the batsmen indulges in fungo hitting,” according to the Art of Batting. Others agreed that the practice was bad for training a batter’s reflexes: “While watching some of our freshmen practicing ‘fungo’ batting the other afternoon it occurred to me that it was about the worst kind of practice a batsman could imagine in training his eye in batting,” a writer claimed in the March 3, 1886 edition of The Sporting Life. “It trains the eye to meet the ball in batting it in a manner which never occurs in actual play. It ought to be prohibited on every well regulated ball field.”
The bat's form has become more refined over time. In the mid-19th century, baseball batters were known to shape or whittle their own bats by hand. This allowed there to be a wide variety in shape, size, and weight. For example, there were flat bats, round bats, short bats, and fat bats. Earlier bats were known to be much heavier and larger than today's regulated ones. During the 19th century, many shapes were experimented with, as well as handle designs. Today, bats are much more uniform in design.
This is the drill we ran all through high school. It is the most time effective and skill intensive way to warm up a team, but your boys must be able to play catch! Fungo-ers stand in the "fungoe circles" that any good field has (and if it doesn't, you know where they're supposed to be - just outside of the home-plate dirt circle, towards the dugouts). The catch to this method is this - you have two first basemen, allowing both sides of the infield to throw across. Herein lies the only danger - one of the firstbasemen has a lengthy throw back to a shagger, so caution must be excersized (a catcher with a good head on his shoulders really helps).
“They’re not moving, their feet are apart, their gloves are on the ground, backs are flat, and they’re working down to up, out to in, basically a steady roll back and forth probably 15 to 20 each,” Bates said. “Then they’ll turn their body, work glove side for another 15 to 20, and backhand 15 to 20. No movement, really, just making sure we’re watching the ball roll into our glove, fielding it, and doing all the things fundamentally correct.”
Fungo bats have been around since the beginning of baseball and as most of us may know, baseball was said to be invented by Abner Doubleday in Cooperstown, New York during the summer of 1839. Since fungo bats were much easier to swing and gave off a ton of pop, they were almost seen as cheating back in the day. In a book from 1897 named "The Technical Terms of Baseball," the sportswriter Henry Chadwick stated,"The weakest batting is shown when the batsman indulges in fungo hitting." It wasn't until baseball bat regulations came around that fungo bats were only used by coaches and parents. 
For starters, we should clarify just what we’re talking about when we say fungo bat. Longer, lighter and thinner than a regulation bat (but a larger barrel), a fungo bat is typically 35 to 37 inches long, and weighs between 17 and 22 ounces. As David Allison wrote in the June 1978 edition of Country Journal, “A fungo bat looks to be a cross between a baseball bat and a broomstick.”