At some point in its service history, the Repulse undertook an asteroid-deflection mission. The energy profile of one of the asteroids warranted a closer inspection and, when in close proximity, a gigantic squid-like lava-creature erupted from it and attacked the ship. Ensnared in the creature's tentacles, the Repulse took heavy damage but managed to fire phasers at its attacker. The confrontation became known as the Battle of Hell's Mouth. (Ships of the Line 2014, Star Trek Ships 2015, ST reference: Ships of the Line)