The Strange Changing Series model kits were sold in 1974 by Model Products Corporation, usually known by its acronym, MPC, a Michigan-based company. The model kits were re-issued in 2012 by Round 2 Models.
Here’s the blurb for The Strange Changing Vampire:
“Open the lid on this ornately engraved casket and you’ll find a snarling vampire leering at you. Close it, open it again and he’s changed into a harmless bag of bones. Close and open it again and the vampire’s back. That’s the Strange Change.”