Gragas is a tanky AP Carry, He got poke from long range and can insta kill people ( squishies )

These runes are very handy, ap runes + tanky, fits gragas very well. Makes him tanky + lots of DMG.

Pros : Very tanky with W + items, Very high AP dmg + AD with Body Slam, can escape easily with E / R , even tho gragas is melee, His Q / R allows him to poke from long range, His fat allows him to squeeze people.

Cons : mana hungry early game, Squishy Until he got to lvl 6

Gragas Ultimate is almost a win in a team fight if used effectively, it can screw up the enemy teams positioning and can take down carries to half hp. Can push enemies where ever gragas wants.
He can also ultimate somone behind, and he'll get pushed into the tower and u can easily pick up the kill. A good combo is throwing out your Q, then throw R and explode Q when your R lands. This can insta kill people. E / R / Q works too if close to somone. Always Have your W available and dont engage without it!, Only if you're forced,

Gragas is a farmer all game long, just throw out your Q at multiple CS and boom u just got 5 minions, E works aswell. Early game consider farming more than trying to get kills. Just poke poke poke and farm farm farm. If you see your enemy not going B just take her out.

Gragas can save enemies with his R and can wait in a bush and when the enemy gets in do E Q R, and boom dead. Make sure you got your ulti ready in all teamfights, the team will need it at most.

Gragas laning phase is great if known how to use. Blue buff is very handy it will allow u to poke without going to use mana pots. Its also very good to get some mana pots until u can afford blue buff from your jungler.

If you have any questions, just ask in the comment section below!