A number of punctuation marks have been devised (but never widely adopted) over the years, in an attempt to textually convey sarcasm and ironic statements. The following is a non-exhaustive list of these in chronological order.
1668 - An Essay Towards a Real Character and a Philosophical Language by John Wilkins, an upside-down exclamation mark to follow irony.
1841 - a Belgian newspaper published by Marcellin Jobard, a large arrow with a small base, similar to a Christmas tree in silhouette. Jobard suggested in later years to have the arrow point different directions to indicate different nuances of sarcasm, hesitation, irritation, and indignation. Jobard also used a reversed question mark in an 1841 article, and commented on it again in 1842.
1899 - L'ostensoir des ironies by Alcanter de Brahm, the point d'ironie "⸮" to follow a sarcastic sentence; de Brahm appears to have borrowed the idea from Jobard.
1966 - Plumons l'Oiseau by Hervé Bazin, the Greek letter Ψ with a small dot below it, to show irony. Bazin also suggested additional punctuation for doubt, certitude, authority, acclamation, and love.
2007 - Collectieve Propaganda van het Nederlandse Boek, the ironieteken, a symbol resembling an exclamation point bent into a thunderbolt squiggle, to show irony.
The only "universal" indicator of sarcasm or irony in English, at the current time, other than explicitly stating something was said ironically, is one used in Internet forum environments such as reddit.
You probably wouldn't know anything about that, though. /s
Iron Noder 2016, 22/30