Ability vs summon sickness

[Hakuu]

Can I use the activated  ability of {Wren's run packmaster} or does it fall under the Summon sickness rule too?

[GoJuDragon]

Summoning sickness only prevents tapping and attacking so u CAN use the ability

🔨

[Imdowd80]

I hate to ask this, but how does his ETB interact with {torpor orb}. Would he be sacrificed because he can't champion another or would, both him and the elf be fine? 

[Bleakone]

I think the champion effect would not trigger so you wouldn't have to champion an elf and he would stay.

[KulrathKnight]

I think the champion effect would not trigger so you wouldn't have to champion an elf and he would stay.

Correct 🔨