Isaac joined in, except he smacked Wyll on the back of the head. Which then caused Wyll to attempt to bite him.

“STOP IT! Dummie!” Isaac yelled out as Wyll lurched toward him. Isaac was Wyll’s twin brother… or well it was complicated. The laboratory where the boys were found showed documentation of only one boy: Isaac. But further information showed they’d extracted his DNA in order to create this mutant— also known as Wyll. Which is how Wyll came about to be the mutant he is, half wolf half boy. In short, Wyll wouldn’t exist at all without Isaac.