Typically, Skull items will not be destroyed when hit by a blast. Instead, the panel will flip onto another tile. In some games, an option can be set to allow them to be destroyed.
As a "bad" item, in some games if a "diseased" player collects a regular item, the Skull will be expelled and flip onto another tile.
If a "diseased" player touches another player, one of two things can happen, depending on the game: the other player will also get the same disease, or the disease will be transferred over to the other player.
Typically, if a player has a disease for long enough, the item will simply disappear. However, in some games, the effects of the Skull will last for the rest of the match.
Surprisingly, in Super Bomberman, despite its multiple bad effects, the Skull possibly can be counted as a good item because it also gives a large amount of points before its effects start. In addition, the Skull can be destroyed by bomb blasts, but only in Super Bomberman, and is also destroyed by kicked bombs, meaning it's not completely indestructible. Additionally, in Neo Bomberman, the Skull is still destructible, but can also be picked up without the bad effects while the player is riding Gaikottsu.
Each game that has a Skull item has a set of possible diseases that players can get from that item. This set varies per game, with the following list showing some of the most commonly seen diseases:
- Rapid Pace Disease (駿足病) - The player moves extremely fast.
- Slow Pace Disease (鈍足病) - The player move extremely slow.
- Diarrhea (ゲリ) - The player continuously sets bombs when possible.
- Low Power Disease (不能病) - The player's bombs explode at minimum blast radius (1 tile from origin).
- Constipation - The player is unable to set bombs.
- Change (チェンジ) - The player switches spots with a different, random player.
Bomberman 64 effects
- Fire - First seen in Bomberman 64 and the only Skull effect that causes direct death to the user. Bomberman is set on fire, cannot drop bombs, and becomes deadly to touch: obviously, because of this it is the only Skull that cannot be "tagged" to another Bomberman. Bomberman will die when the effect expires, which takes about 30 seconds. He is not invincible, and will detonate bombs if he touches them.
- Reverse Movement - Reverses the function of the analog stick: Bomberman walks at full speed in whatever direction he is facing with the stick neutral, slowing down as it is pushed further and stopping completely and turning on the spot if it is pushed fully in a direction.
- Low Power Disease - Bombs explode at minimum blast radius, even if pumped.
- Big Bomb Disease - Bomberman drops bombs that look normal but have the maximum radius blue explosions of a pumped-up red bomb (if Bomberman already has red bombs this will be obvious as they will turn black). Pumping bombs no longer has any effect on blast area. The Maximum Evil item does the same to all players.
- Quick Bomb Disease - Bombs explode after 2 seconds instead of 5.
- Big Bomber Disease - The game's variant of Slow Pace Disease. Slows Bomberman down and also makes him grow significantly in size. The Gulliver Evil item does the same to all players.
- Small Bomber Disease - The game's equivalent of Rapid Pace Disease: Bomberman becomes very small and incredibly fast, almost uncontrollably so.
- Diarrhea - Bomberman continuously sets bombs when possible.
- Constipation - Bomberman is unable to set bombs.
- Baron Bombano has the ability to generate a Skull item, which will flip onto the field.
- Witch Bomber actively seeks to pick up Skull items in the Battle Mode of Bomberman World.
- Dr. Mook and Carat Diamond has the ability to generate Skull items from Uiteru V.
- Bomberman '94 U.S. manual, pg. 19
- Bomberman Quest Official Guidebook, pg. 17