Partial invisibility effect

Partial invisibility is a visual effect which affects the player when he picks up a blur artifact and the Spectres by default. Albeit the game logarithm allows any object to be partially invisible, in official game play these are the only occurrence when the fenomenom can be seen. The concerned thing retains its shape, but instead of color we see black pixels scattered randomly (applied by colormapping the pixels behind it to darker shades), which makes the object more difficult to see.

When the player is in such a status, the monsters' behaviour change. They can still spot and assault him, but both projectiles and melee attacks will be badly aimed, and will be scattered on a large firing angle, thus reducing the possibility the player being hit. However, in case a moving player faces one or more monsters who throw fireballs, their projectiles became more dangerous. Infact, if aimed properly, the player can easily avoid fireballs by changing his position by the time they reach his original emplacement, but if they are randomly aimed, they may hit the player on his new place.

In Heretic, Hexen, and some source ports, partial invisibility is achieved by translucency (using the TINTTAB color map).