
I was watching the 2011 Thundercats Episode 7: Legacy and I noticed this few seconds shot of Mon*star from Silverhawks in one of the video displays in Mummra's ship. I am supposing this is to pay homage to the late Earl Hammond who voiced Mummra and Monstar in the 80's. Mighty fine of them producers in doing this homage to a great voice actor.
Video below to give you an idea as to who Mon*star was.
Episode 7 of Thundercats 2011 took a look into the origins of the ThunderCats and how they landed in 3rd Earth together with Mummra and the other Mutants.