Portal 2 Lemon Grenade Mug When life gave Valve lemons, they didn't make lemonade. Instead, they invented this awesome Portal 2 Lemon Grenade Mug! Not only is this mug's look inspired by Portal 2, but the function is as well, because it features a pin that actually pulls out of the mug as well. The Portal 2 Lemon Grenade Mug is made from ceramic and holds up to 12 oz. of liquid.