Q:

What happens to a Giant Toad with a Lightning Staff?

If I'm playing a druid who has taken a Lightning  Staff for Mark of Storm cheese, and I summon a giant toad, is its tongue electrified such that I can benefit from mark of storm from its attacks? 

A:

Yes.
Summon Giant Toad is an implement power, and the standard action attack does not have keywords of it's own so it inherits them. You are channeling your control of the toad through the staff and all damage from the toad is lightning damage.

