When eaten, bat wing has a hyphen between it, but otherwise doesn't. Odd.
References
"Pow!", "Biff!", and "Socko!" are examples of onomatopoeia from the 1960s Batman television series starring Adam West and Burt Ward. Fight scenes were overlaid (in the first season) or interspersed with full screen-shots of words such as these, with audio accompaniment, in imitation of comic-book sound effects.