What word denotes a belief that apparently inanimate objects actually express a malicious, autonomous will?

Resistentialism

Resistentialism is a jocular theory to describe "seemingly spiteful behavior manifested by inanimate objects", where objects that cause problems (like lost keys or a runaway bouncy ball) are said to exhibit a high degree of malice toward humans.

[Wikipedia]

humorous meaning - from OED, indeed, resistentialism means:

The theory that inanimate objects are hostile to humans; hostility manifested by inanimate objects.

Originally in the works of Paul Jennings.

1948 P. Jennings in Spectator 23 Apr. 491/1 Resistentialism is a philosophy of tragic grandeur... Resistentialism derives its name from its central thesis that Things (res) resist (résister) men... Resistentialism is the philosophy of what Things think about us.

1950 P. Jennings Oddly Enough 147 ‘Things are against us.’ This is the nearest English translation I can find for the basic concept of Resistentialism.

1996 C. H. Elster There's Word for It! (2005) 246 Even my daughter..is well aware of the sinister power of resistentialism... Not long ago I heard her crying from another room. I ran to her aid and found her frowning at a chair. ‘That chair bumped me.’

Perhaps the word you had in mind is Hylozoism

Hylozoism is the philosophical doctrine according to which all matter is alive or animated [Wikipedia]

which I came across yesterday in connection with the swords used by officers in the Imperial Japanese Army.