The bredlik, also known as a »cow poem«, »my name is cow« or »I lik the bred«, is a novelty meter originating with a popular piece of doggerel posted on the webhole Reddit. It was prompted by an amusing anecdote about operating a reconstructed early-modern bakery in a Canadian living history museum, was a brief fad over a year ago and has probably lost most of its popularity by now. Novelty poetry per se is nothing new, of course; on the contrary. In this case the clearest antecedent is perhaps the clerihew, where the point is to deliberately end the first line with a difficult name just so you can then rhyme it; an obscure form known as the »limerick« also shows more than surface parallels to the bredlik.
Functionally, the bredlik is the perhaps simplest of all possible verse forms to construct in English: an iambic tetrameter rhymed AABB.
This mayks it fytte
for doggerel;
no fuckyr wraits
a villanelle
wyth simpyl eas
from top of hed —
but this coms swyft.
It servs the bred.
As you can see it's formatted as a quirky dimeter rhymed CADAEBFB, but this is a purely typographic trait and not a structural one of the poem per se; »a poem where every other line rhymes« does not, in any functional sense, exist. You can write blank verse, but not half-blank. (Whether there is or is not a cæsura in each line of the tetrameter is, I think, a debatable point; I myself would argue that the last line only contains one, represented by the blank line.) The formatting should not be dismissed, however: a proper bredlik will contain the excess linebreaks, the dash at the end of the »sixth« line, the periods at the ends of lines »seven« and »eight«, and the blank line (optionally two) between them. Whimsy also demands frequent comical misspellings, basically because the conceit of the original poem was that it was written by a marginally literate cow. Finally, the only capital letter employed should be the initial of the speaker's name.
Arguably, there are also topic restrictions, as in haiku: an exacting person could demand that a proper bredlik should start with the speaker declaring his name, that it should have a temporal reference in (at minimum) the second »line«, and that both of the last »lines« should be declarative and start with the pronoun »I«. My example above, in other words, is not orthodox. I can only plead that I made it up off the top of my head with no revision, to illustrate the principle of the thing, and also that I don't care even a little bit.
Despite all this structure and limitation, the crux of the matter is that, as I have already remarked, it is extremely easy to improvise a few lines of such doggerel, making it suitable for spontaneous and ex tempore poetry, an art, like puns, much practiced among the ancestors, but seldom now. Inevitably, such poetry is seldom of the first water; it is more about amusing others in and with the moment than about producing the perfect and timeless. In this sense it is time well invested; there are plenty of people in this world who would do better to hone their conversational wit than shoot for the eternal, and even more who need an ordinary laugh far more than they need sublime emotions.