Chatcharn Buppawan (), known as Puchana (), was a Thai anti-monarchy activist and exile based in Laos. 
Activism and exile.
Chatcharn was a member of Red Siam, a republican faction within the Red Shirts political movement. He fled Thailand following the 2014 Thai military coup. In Laos, Chatcharn lived with exiled Thai activists Surachai Danwattananusorn and Kraidej "Kasalong" Luelert in Vientiane. 
Disappearance and death.
On 12 December 2018, Chatcharn, Surachai, and Kraidej disappeared from Vientiane.
On 26 December 2018, Chatcharn's mutilated body was found by fisherman Denchai Sornsai on the shore of the Mekong River in northeastern Thailand. The body of fellow activist Kraidej Luelert was found in a similar location on 27 December. Both bodies were found to be disemboweled and stuffed with concrete posts. The killings of both activists were described as political in nature.