Valmiki Ramayana Aranya Kanda Sarga 24 Shloka 26

अक्लिष्टकर्मणः of one who is unwearied in action, तस्य his, रामस्य Rama's, अप्रतिमम् incomparable, रूपम् form, क्रुद्धस्य of an angry one, पिनाकिनः wielder of Pinaka, रुद्रस्य Rudra's, रूपमिव like the form, बभूव appeared.

Rama, who is unwearied in action and who is of an incomparable (lovely) form, looked ferocious like the wielder of Pinaka (Lord Siva).