This is a plastic Huge Fire Elemental by WotC, from the 2006 War of the Dragon Queen set. It's chasing a lead Zombie by Grenadier, from the 1980 Dungeon Monsters box set.
I woke up abruptly at 2:30 am after only a couple hours sleep and my brain said ‘Take that big transparent fire elemental, you have two. Cut a hole in the bottom. It’s hollow. Put an LED taped to a battery in the hole. Paint Citadel Mordant Earth on the outside. It’s a black crackle paint and will look like lava.’
I said ‘You’re right brain, that’s a good idea, but was I thinking about fire elementals? Where did this come from?’
Brain said ‘You can sleep while the crackle paint dries.’
More pics here: http://www.terrainosaur.com/blog/2020/07/27/i-am-the-god-of-hellfire/.