Big people, mostly those who have smoked cigarettes a lot, get two different kinds of Terrill the Terrible that grow in Lyle Lung. Kids very rarely get Terrill as the first place he attacks them. Mostly Lyle only gets involved if Terrill has grown somewhere else in their body first and has gone to the lungs to set up a condo in addition to his original house. Captain Chemo is often the one who comes to help if Terrill has gone to the lungs.
If Captain Chemo and Zapman have been fighting Terrill your body sometimes make enough of Ben Blood - if you come in contact with a bad cough or cold the battle is often fought inside of Lyle. It's also a hard battle because you are weak - that's why those taking care of you will give lots of antibiotics or antivirals to help your body get you well.