def f(&block)
     block.class
   end

   f { } # => Proc
   f(&-> { }) # => Proc
   f(&lambda { }) # => Proc
   f(&:something) # => Proc

   lambda { }.class # => Proc (I think you get the idea)

   method(:f).class # => Method

   lambda { |i| i + 1 }.call(10) # => 11

you don't typically return in a block, there is implicit return. you would do "next" or "break" depending on what you want to achieve. as far as I know that's the main difference between procs and methods.

(not that anybody would do what I do, most people just use blocks, some people use yield, few people use the &block argument, but that's exactly the same)