蚊遣り豚 kayari buta: a ceramic mosquito-incense holder shaped like a pig. Sometimes written as just 蚊遣豚. Buta 豚 means pig, ka 蚊 means mosquito.
蚊取線香 (also seen as 蚊取り線香) katori senko: mosquito repelling incense, usually shaped in a coil. Senko 線香 means incense.
Kayaru buta is frequently seen around Japan during summer time, so it is a sort of symbol of summer. It is cute I think.
I bought one at Makeman メイクマン (DIY Home Store) in Okinawa. I think it is the most generic type, but it has a feeling of nostalgia. I saw some really expensive ones on Amazon.jp, they were very pretty though. Sometimes the smell of the incense is a little strong, but I guess it keeps the bugs away well enough so I don’t mind using it outside on my upstairs lanai. You cannot tell from the picture but smoke wafts from his snout as the incense burns. We bought the Cainz home store brand incense instead of 1 of the 2 big name brands here in Japan; I think it works just as good.