Getting drank

Beavertown Brewery currently have these billboard adverts up, with the slogan Out of this world beer. Drank on Earth: 

Photo: @nicholasd on instagram

The verb drink is one of our irregular verbs, as it doesn't have a past tense of drinked, adding the regular past tense ending -ed, and instead changes its vowel, so you say I drank beer not I drinked beer. It also does this for the participle, which is what you use for various things including perfect aspect (I have drunk beer) and passive (The beer was drunk by me). This passive participle is also the one we use for things like relative clauses (The beer that is drunk on Earth). 

But there is variation! Not everyone has all three of these forms in all contexts. For a lot of people, drank is used for all the non-present forms (I drank the beer, I have drank the beer), while for others, drunk is used (I drunk the beer, I have drunk the beer). For everyone, the adjective is drunk, though (no one says I am drank!), which I think is a nice indication that it's somehow separate from the verb. 

In formal English, then, this slogan would say Out of this world beer, drunk on Earth, because it's the relative clause type: this is short for which is drunk on Earth. They've chosen instead to go with the form used in more informal contexts and said Drank on Earth. The company's image is very informal and friendly, so they presumably felt it fit more with that vibe, and it has the added benefit of not being mistaken for the adjective which might imply getting drunk, not a good look from the point of view of the advertising standards people.