[TOMT] Anime(?) I saw about a few teenagers go to what I think is an antique shop, and sometime during that having the ability to turn into mini mechs(???) in a different world to fight something [TV SHOW]

It was something that I’ve desperately wanted to see, and I remember watching it in 2012, 2013, or something like that. I think it could’ve been on Cartoon Network but I don’t know. I also remember one of the main characters being turned into a red monkey for a few episodes. I feel like it could’ve just been a fever dream but honestly I really hope it isn’t. I think there were separate episodes for some main characters finding out about the antique shop on their own