Tag 667

Tag 667, closely related to tag 666, is used on Doom 2's MAP07 in conjunction with the Arachnotron. This is the relevant code (from p_enemy.c, lines 2180-2185 in prBoom 2.2.6):

if (mo->type == MT_BABY) {             junk.tag = 667; EV_DoFloor(&junk,raiseToTexture); return; }

When the last Arachnotron dies, any sectors tagged with the number 667 are raised up by the height of the first sidedef's lower texture. If the first sidedef does not have a lower texture, the second sidedef is used.

Bugs
Sometimes, if the last two Arachnotrons on MAP07: Dead Simple are killed nearly simultaneously, the step to the exit switch rises twice. (In this case, the level can still be completed by jumping to the step from one of the square metal platforms.)