Offering to the Snake Deity

The only card I control is a face-down Call of the Haunted card. My opponent attacks with a Reptile-type monster. I activate Call of the Haunted to special summon Thought Ruler Archfiend from the graveyard. When it's already summoned, can my opponent activate Offering to the Snake Deity, and if the answer is yes, can it be negated with the effect of Thought Ruler Archfiend? The trap card obviously targets, but not just one card... so I'm confused here.

Any explanation? Thanks.

He's free to activate Offering to the Snake Deity after Thought Ruler Archfiend is Special Summoned and Call of the Haunted resolves.

Because Offering is not targeting only just 1 Psychic Monster, but rather the Reptile, 1 Psychic, and Call of the Haunted, Thought Ruler cannot negate it.

Tcbskater wrote:He's free to activate Offering to the Snake Deity after Thought Ruler Archfiend is Special Summoned and Call of the Haunted resolves.

Because Offering is not targeting only just 1 Psychic Monster, but rather the Reptile, 1 Psychic, and Call of the Haunted, Thought Ruler cannot negate it.

Similarly to Spirit Reaper, Reaper does not die if it's targetted by something that has multiple targets, i.e. Gyzarus (Though gyzarus would destroy it anyway, just for exampl's sake)

XVI wrote:

Tcbskater wrote:He's free to activate Offering to the Snake Deity after Thought Ruler Archfiend is Special Summoned and Call of the Haunted resolves.

Because Offering is not targeting only just 1 Psychic Monster, but rather the Reptile, 1 Psychic, and Call of the Haunted, Thought Ruler cannot negate it.

Similarly to Spirit Reaper, Reaper does not die if it's targetted by something that has multiple targets, i.e. Gyzarus (Though gyzarus would destroy it anyway, just for exampl's sake)

Um, no. Spirit Reaper was still targeted. The thing with Thought Ruler is that it specifies that exactly 1 Psychic monster has to be targeted for the effect to be activated. Is Spirit Reaper and another card are targeted by Gyzarus and Reaper somehow survives, it was targeted and it's own effect kicks in.