Giga Bowser and Valoo are respectively from Nintendo's Mario, Super Smash Bros. and The Legend of Zelda: Wind Waker and this screenshot's taken from Valve's Garry's Mod. Requested by  AsBoyz2017 and  David-967.

These dudes challenged each other to some P-Balloon inflation match and it looks like Valoo is winning. In the meantime, both of their bellies are growling loudly, meaning that both their fire breaths may cause their stomachs to bloat up even further. All units, better stand clear.