In episode 26 of Ultraman Ace, Ace fights the alien Hipporito but is trapped inside a chamber and turned into a jade statue. Before the transformation is complete, he summons the other Ultramen. Two of them are trapped shortly after arriving, with the third trapped as he tries to free them. The final Ultraman fights the monster but is soon inside a chamber. All four are then turned into jade statues, as we see the five former heroes decorate the landscape as the sun sets.
More here: http://ultra.wikia.com/wiki/Alien_Hipporito#Ultraman_Ace