Vampire's may not get sick, but Marshall is good at faking, and Fionna and Gumball go over to set him straight.
When they got to his home, Fionna clambered out of the boat and sped to Marshall's door, kicking it open with force. Gumball carefully arranged the mooring on the deck, not wanting his main mode of exit to go floating away. It would not be suitably princely to come back floating to his palace under the arm of the local vampiric cad, no matter how much he loved him. By the time Gumball had made his way into the house, Marshall was already shrunk away against the headboard of his bed, Fionna yelling angrily at him for his misdeeds.
"Because honestly Marshall, your flipping boyfriend and girlfriend wouldn't know a globbing thing about Vampires, and know you were lying to them! Like a flipping git! What is wrong with you sometimes?" She wasn't sure if she was asking him or herself, but she left out an exasperated huff and crossed her arms. Gumball tutted and frowned at them both.
"Fionna, calm down. It should be obvious why he went through all the trouble," and this word he emphasized with a look in the vampire's direction, "to call us up, lie to us, and even face an angry you." She gave him a most quizzical look, and if anything, Marshall looked more sheepish than he already did, surrounded by blankets and curled up small, trying to back away from his mistakes.
Gumball began to stride toward the bed, dragging Fionna along with him and shrugging off his coat, before he sidled the two of them on the bed on either side of Marshall, and then he wrapped his arms around the vampire and kissed his cheek. Ashen cheeks turned crimson, and Marshall put his chin to his own chest to hide his face. "He's feeling lonely and all. When you or I get sick, we get all the attention from others, but he doesn't get sick, and he doesn't get the attention the same way. He's always going to be a big kid, so what more can you expect from him? He's still lovable." Fionna's arms joined Gumball's in wrapping around the gray king, and she nuzzled his neck.
"You should have told us Marshall. Honestly. You made me all mad at you, and I hate being mad at you." Marshall flashed them both a grin that wasn't quite as big as normal.
"Actually, you're only half right." He let out a sneeze that rocked the bed, and then coughed himself sore for a few moments, before pulling himself out from them to go and get tissues. "I do miss you all, and I'm a big jealous I'll admit. However, I'm not a born-vampire. Half-demon blood." He sneezed again, this time thankfully into a tissue. Fionna gave Gumball a crooked smile, and the two hoisted Marshall back into bed, tucked blankets around him, and proceeded to take very good care of their vampire until he was better.
Notes: This wasn't the best thing I've ever written, but it definitely works fine for now. I'm just getting more familiar with my style and going through some junk in that big ole real world, but I should get back into a groove soon, I hope.