[A joke post] Singed is actually an assassin/skirmisher hybrid

http://na.leagueoflegends.com/en/news/game-updates/gameplay/dev-blog-classes-subclasses

Assassins specialize in infiltrating enemy lines (proxy farming) with their unrivaled mobility (Insanity Potion and Ghost) to quickly dispatch high-priority targets (minions). Due to their mostly melee nature, Assassins must put them themselves into dangerous positions (the enemy base, and often under enemy tower for execute) in order to execute their targets. Luckily, they often have defensive tricks (Defensive Bulwark, Mega Adhesive, Fling, Insanity Potion) up their sleeves that, if used cleverly (dodge skillshots with high MS steroid from Insanity Potion and slow/snare opponents with Mega Adhesive and Fling), allow them to effectively avoid incoming damage.

Furthermore, I've found some more disturbing facts.

Unlike Assassins, Skirmishers aim to shred through any nearby enemy that approaches (thus the phrase, "don't chase Singed"). Because Skirmishers lack high-end burst damage (his Fling is the only source of burst) or reliable ways of closing in on high-priority targets (no dashes, only MS steroid on Insanity Potion), they are instead armed with situationally powerful defensive tools (Fling and Insanity Potion) to survive in the fray, along with extreme sustained damage (Poison Trail) to cut down even the most durable targets.

Singed is an Assassin/Skirmisher hybrid. Not a tank, not a fighter.

######This is a joke post. Singed is not actually an assassin/skirmisher, and I don't actually think he's an assassin/skirmisher. Riot categorizes him as a unique playstyle.