wouldn't he have to have a summoning first.. <.< he can summon dead people , but animals I haven't seen affiliated with him. he is scared of animals like he is scared of uchiha.. xD

After his discovery of senjutsu damaging obito I'm hoping that we will see a tobirama sage mode. He knew toad sage mode , maybe perfected beyond naruto toad sage or water dragon sage That's whati want to see
Dat Penguin sage mode though... Aha.
Genma comes back with Ninpou - Senbon Kuchiyose no Jutsu. It summons a living senbon that was used by the sage himself. It resides in Mt. Senboyokou. it has the ability to seal anything that gets within 2 feet of it. It's chakra shroud reaches out 2 feet obviously. Genma wields this, along with his normal arsenal of senbon. his normal senbon can also be used along with FTG, which don't require tags. Genma can also activate his senbon sage mode.