A wager cup (also termed a ‘drink-up’) is so-called because the user could not set it down when it was full and thus had to drain it. Wager cups came in all shapes and forms. The one here is shaped like a cannon; the mount, or carriage, is missing. The cup is embellished with the name of Jesus; the salvation of one’s soul was paramount, even during a drinking-bout.

You could even say it’s a literal glass cannon