Hotheads (パサラン, Pasaran) are items that, when thrown, will slide across the ground releasing bursts of sparks and damaging opponents of the character that has thrown this item. When hit with fire or electricity-based attacks, they grow bigger, dealing more knockback. However, in contrast to what its trophy says, there is an upper limit to how large the Hothead can become (roughly three times its original diameter).
It must be picked up and thrown to be activated. Once the Hothead lands on the ground or a platform, it will move along the surface in the direction it was thrown and periodically release sparks, which are almost 2 times as strong as a smash-thrown hothead of the same size. A Hothead can continue to grow after it is thrown. If it is thrown onto a stage, the Hothead will cling onto the stage's walls and surface. If, however, it lands on a platform, the Hothead will simply roll off until it finds solid ground (or just falls off the screen). Hotheads eventually disappear in an amount of time inversely proportionate to their size (that is, bigger ones vanish faster).
A hothead will reach maximum power after it takes approximately 30%. But if the hothead is undamaged and hit by a fire or electric based attack that deals over 30% (such as Ike's Eruption), its power can exceed this limit and gain OHKO power. This can be taken to ludicrous extremes by knocking five Soccer Balls into a Hothead using Marth's Critical Hit (only in Training Mode is this plausible), causing the Hothead to deal 140% or more and becoming impossible to reflect.
Note: All of these damage percentages were taken with an uncharged Hothead.
In Super Mario World, Hotheads were enemies that appeared inside Wendy Koopa's Castle on World Six, Choco Island. This level largely comprised of stone blocks, which had Hotheads constantly moving around them. Unlike those in Super Smash Bros. Brawl, they were not enlarged by fire and they never disappeared.
 Trophy Info
An item that, when tossed, sticks to the terrain and moves, causing damage to those it touches. Whoever threw it won't take damage. It will grow larger if it's attacked, which ups its attack range. However, an increase in size corresponds to a decrease in the time it stays on the screen. A really big Hothead will take up the entire screen, and is quite a sight to behold.