I thought the poking was fine for all bosses (almost never had one escape), until event 21 or 22 when the summoned bosses seem to be tougher. It gave more people a chance to get in on the rewards, because everyone who participates gets the same amount. I think the summons are even stronger now than event 21/22. That first event with the upgraded bosses, I could do about 650k damage, now I only do about 450k. Maybe it has to do with the element type. But I've been looking back at some of the escapees, and many of them didn't have any pokes. Just not enough people responding or people who didn't do enough damage. Now I think I'll ignore any phase 2 summons where the summoner didn't use at least 2 points, or if the timer is short.

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I would also say that poking shouldn't be done anymore, though, since the event bosses have been upgraded.