Proficiency

The huge stone axe barely missed the cleric's head.
"Train!" the living statue bellowed.
The sorceress lobbed a scorching ray towards it.
"Train!" it shrugged it off, apparently immune to magic.
The paladin, who seemed to be the only one not targeted grinned.
"It's a golem," he explained as one more of his companions barely dodged a blow. When none of the party reacted with more than nasty looks, he added: "A drill sergeant golem, meant to train new recruits."
More glares.
"Alright, stop. Training over," he finally said. "Time to go home."
"Train?" the golem asked, but then followed.