It's Alloy, rookie Super horse in Act I of Tannhäuser!

Alloy is owned and trained by Gary Sello of Novato. They appear onstage together with Eric Halfvarson and the hunters as they discover Tannhäuser, back from his adventures in Venusberg.

Alloy, seen below with Mr. Halfvarson astride, heads in to pick up his ID card and wait out in the House for his call.

There has been no comment as yet from Django, the Wonder Dog, of Der Rosenkavalier fame.