hydra2

(global-set-key
   (kbd "C-x k")
   (defhydra hydra-kill-buffer
     (:color pink)
     "kill-buffers"
     ("k" kill-this-buffer "kill current buffer")
     ("c" kill-buffer "kill buffer cycle")
     ("a" kill-all-buffers "kill all buffers")
     ("o" kill-other-buffers "kill other buffers")
     ("q" nil "quit" :color blue)))

 (defun kill-all-buffers ()
    (interactive)
    (mapc 'kill-buffer (buffer-list)))

  (defun kill-other-buffers ()
    (interactive)
    (mapc 'kill-buffer (cdr (buffer-list (current-buffer)))))