I recently encountered an expression that seems like it would be pretty common, but in almost two years of study I hadn’t come across before. It also features a verb I don’t think I had seen before, one of those which only occurs in the third person. The expression is

skaðinn er skeðurthe damage is done

skaði (m) – damage, loss
singular plural
nom skaði skaðar
acc skaða skaða
dat skaða sköðum
gen skaða skaða
að skaða – to damage, harm
present past
ég skaða skaðaði
þú skaðar skaðaðir
það skaðar skaðaði
við sköðum sköðuðum
þið skaðið sköðuðuð
þau skaða sköðuðu

I found another instance of it – enginn skaði skeður – which I think means no harm done.

As it turns out, skeður is a past participle form (declined like an adjective) of the verb að ske, which only appears in 3rd person singular/plural forms.

að ske – to occur, happen
present past
það skeður skeði
þau ske skeðu

Beyond finding a few examples of ske in action, I can’t say I have much of a grasp on when it is used exactly, as opposed to the other ways to express happen, occur – the most familiar might be að gerast:
Hvað gerist eftir…What happens after…

There is also að koma fyrir:
Oft kemur fyrir að…It often happens that…

So an interesting expression with a weird verb 🙂