without using any time. Targetting an apparently empty spot at valid polearm range where a monster happens to be hiding reports "Wait! There's something there you can't see!" and displays the remembered, unseen monster glyph, then aborts the attack attempt. It would use a turn if the polearm became wielded in the attempt but not if it was already wielded. Make latter case take time.
130 KiB
130 KiB