elixir, 215 bytes

Result

AC

Duration

2510ms

Code [DL]

defmodule F do
def f(s,t)do
case IO.gets("")do
:eof->IO.write String.slice String.trim_trailing(t)<>String.duplicate("*",99),0,String.length String.trim_trailing s
t->IO.write s
f s,t
end
end
end
F.f IO.gets(""),""

stdin

           T                                      
                                                  
                                                  
                                                  
K                                                 

stdout

           T                                      
           T                                      
           T                                      
           T                                      
K***********

stderr

strace