Answer: This 71-year-old game show host snapped his Achilles tendon while chasing a criminal through a San Francisco hotel this morning.

Question: Who is Alex "DESTROYER OF EVIL" Trebek!!!!!!!!!!!?!?!?!?!!?

Trebek -- perhaps the greatest Canadian who ever lived -- crutched his way into the National Geographic World Championship at Google headquarters in CA today and explained he was trying to catch a burglar when the injury occurred.

Trebek says he's feeling OK.

It's unclear if the suspect was ever captured ... or what he allegedly stole ... but we're willing to wager that Alex won't rest until JUSTICE is served!!!!

UPDATE: The suspect has been ARRESTED ... and according to ABC7 in SF ... the alleged bad guy is actually an alleged bad girl.

Cops say a 56-year-old woman was booked on felony burglary and possession of stolen property after allegedly entering Trebek's room and taking cash and a bracelet his mother gave him ... and then stashing it near an ice machine on Trebek's floor.

Trebek injured himself while chasing the woman down the hallway.

*THIS HAS BEEN A MERV GRIFFIN PRODUCTION.*