This "steam" seems to go out from something equivalent to the Roman
rostra (
Naval ram - Wikipedia;
Rostro (arma) - Wikipedia), which were said to be "symbolic decorations".
I've never really understood this fashion of putting naval rams on columns!!!
Also, speaking about enemy trophies (I know it's not related hehe), ancient Greeks erected a
tropaion (
Tropaion - Wikipedia) "on the battlefield itself, usually at the site of the "turning point" (Gk.
tropê) at which the routed enemy's phalanx broke, turned and ran. It would be dressed in the typical hoplite panoply of the period, including (at different times), a helmet, cuirass (either of bronze or linen), and a number of shields, etc., would be piled about the base. It remained on the battlefield until the following season's campaigns (since battles were often fought in the same, relatively few plains amid Greece's numerous mountains), where it might be replaced with a new trophy". Romans called it a
tropaeum. Don't they remind scarecrows?