Ultraman S35E15 - Betwixt Morn and Dusk

Gento's son, Jun is classmates with an unusual character, Arata. One day, Arata half-forcefully brings Jun to his secret base filled with his drawings of kaiju. Jun is moved by Arata's passion behind the drawings and his free-spirited soul. Jun draws a kaiju of his own and named it Gavadon. When night falls, a mysterious ray of light transcends down to the secret base and the drawing of Gavadon begins to beat like a heart.