This shirt doesn't make any sense. No virus in his right mind would attack a RBC because RBCs don't have any DNA or any of the machinery a virus would need to replicate itself.
On a serious note though, I really like this, but what if instead of attacking a cell, the megavirus was attacking like a person, or a bear, or a whole city or something.
Ooh, you could have one fighting with a bear in the foreground, and in the background a dead bear carcass with a big megavirus latched onto it and a whole bunch of small megaviruses crawling out of it's ruptured gut. Did I just go to far?