I feel this glyph needs some attention. It's slowly been suffering from changes made throughout the beta. From the experience curve change, to the slowly increasing value of popcorn monsters, to the generally more clog-prone monster positioning, the glyph has been hit by one indirect nerf after another. The recent change to its interaction with slowed monsters correctly identified that it had a dissonance with WEYTWUT and WONAFYT, but failed to address the real problem: IMAWAL removes popcorn monsters from play, preventing you from capitalizing upon them later, and its effect really isn't strong enough to justify this heavy double-edge.
Now, IMAWAL does shine when you're an Earthmother worshipper or if there are plentiful no-XP enemies to target, but in the baseline case the glyph is highly questionable. In most maze-style dungeons it's completely suicidal unless ENDISWAL spawned with it, and even in other dungeon layouts it's often unusable just by the luck of positioning.
I believe a secondary effect is in order, one that only triggers when using it on an XP-granting enemy. Here are a few suggestions:
* 40% temporary magic resist (as the counterpart to ENDISWAL)
* 10 CP per level of the monster petrified
* gain increased health and mana regeneration for the next few tiles you reveal (effect is stronger based on the level of the monster petrified)