I've never seen that but cider and guinness?
Guinness improves everything.
It's a rule.
I don't like Guinness
Well, except in Irish stew eat0
I like the Strongbow because it's not a sickly-sweet that some of the other major brands are over here.
I generally top off a Strongbow with a Guiness and as long as it's poured right, the gravity will hold.