The Book of Pennywise

[Arkham]

What about something like this?

Attack = 4

IT
When Pennywise attacks a figure without the Fearless or Insane personalities normally, you may re-roll all dice once for each of the following that is true about the defending figure:
• It is small or tiny.
• It does not have the Super Strength special power.
• It has a Wound Marker on its card.
• It is not adjacent to any figures it considers friendly.
• It has no Order Markers on its card.
Pennywise cannot attack a figure with the Fearless personality.

So he can keep shifting the assault(re-rolling all dice, not just specific ones), a number of times based on how likely they are to be afraid of him(each bullet). Quickly going from one shape/appearance to another, messing with them, until he gets the roll he wants.