Guard & zone attack

[Donovan]

When an earth elemental finds himself in a zone with a guarding Watchdog, is he allowed to use his zone attack (which would also attack the Watchdog) or is he supposed to use his Melee attack to attack the guarding Watchdog?

[Halewijn]

Even with guards, you can always target the zones, the walls, yourself and anything attached to yourself.

So, yes you can do the zone attack.

[iNano78]

... in contrast with Taunt, which would force the Earth Elemental to use its melee attack against the source of Taunt (e.g. Sosruko or Thorg).

[Kaarin]

Guarding only limits available targets for melee attacks in the guard's zone. Guarding doesn't limit which attack You can make so there's nothing that prevents You from using ranged attack like Earth Elemental's quake stomp.

[Laddinfance]

You've all answered the question splendidly. Enjoy your Banana sticker.