Update: Simmons has since commented on the matter via Twitter, saying "Ok, kids. Not a big deal. Thanks for your kind wishes. Last night we played Amazon jungle Stadium/Brazil. Humidity and temperature were sky high. I was dehydrated and was forced to sit for a song. We got back on stage in 5 minutes & finished the show."
Original story: Kiss frontman Gene Simmons fell ill midway through a show in Manaus, Brazil on April 12. According to G1, Simmons asked the road crew to bring him a chair during a performance of "Say Yeah", and then played the rest of the show sitting down.
Kiss guitarist Paul Stanley addressed Simmons' ailment from the stage during a break, saying "We're gonna have to stop to take care of him, 'cause we love him, right? Let's give Gene a really loud 'Gene'." Kiss then took a five minute break, with Simmons returning to the stage to thank everyone for their support.
We wish Simmons all the best and hope everything is alright. Blabbermouth points out that one common theory about Simmons' illness was that it was heat exhaustion, considering it was around 80 degrees Farenheit that day. Which of course means it was hotter on stage, and even hotter under that huge costume.
