In classical Greek and Latin meter, a line of dactylic hexameter alternating with a line of dactylic pentameter was called the “elegiac couplet.” Here’s an example from Ovid:
Arma gravi numero violentaque bella parabam
Edere, materia conveniente modis.
Par erat inferior versus: risisse Cupido
Dicitur atque unum surripuisse pedem.
English version by Dryden:
For mighty wars I thought to tune my lute,
And make my measures to my subject suit.
Six feet for ev’ry verse the muse design’d,
But Cupid laughing, when he saw my mind,
From ev’ry second verse a foot purloin’d.
These lines actually talk about the meter they’re written in! (But Dryden’s version is iambic pentameter, pay no attention to it, I just cited it for meaning.)
Poetry is one of my least favorite subjects, but I can tell you a few things before a real poetry expert shows up.
You spelled it correctly.
Dactyl is from the Greek for “finger,” thus a dactylic foot (odd combination, isn’t it?), like your finger, has three parts, with an emphasis on the first: DAH-da-da.
Therefore dactyllic pentameter would be poetry in which each line was fifteen syllables, five dactyls:
Not being a fan of poetry, I can’t think of any works in dactylic pentameter.
There is a form called the double dactyl which has an interestingly strict format:
Two verses of four lines, each line is two dactyls.
The last lines of each verse rhyme.
The first line has to be a nonsense term, like higgledy-piggledy.
The second line has to be the name of the subject of the verse.
One line has to be to be a single word.
For instance:
Higgeldy, piggeldy,
Benjamin Harrison
23rd president
Was, and as such,
Served between Clevelands and,
Save for this trivial
Idiosyncracy,
Didn’t do much.
A google on “double dactyl” will provide plenty of examples.