[Professor Scott]

Though come to think of it, this can happen with the phrase "one time captain", though I see no instances of that in the card database.

Since former is shorter than one time (one-time), you probably never will, but it is a good point, nonetheless.

[AllenGould]

We do have a few cards that trigger on "Once in play", so I guess you could play Mortal Q the first time without closing your Flash, because it'd now be "Twice in play," ?

[Professor Scott]

Oonce...tice...fee tines a mady!