Put X glyph counters on target creature that target Wall blocked this turn, where X is the power of that blocked creature. The creature gains "This creature doesn't untap during your untap step if it has a glyph counter on it" and "At the beginning of your upkeep, remove a glyph counter from this creature."
Can be cast at any time after the wall blocked a creature and can affect any creature that the wall was assigned to block or that was blocked by the wall due to being in a band or by being switched into or out of the block by an ability.