The Living Monolith can
A living monolith can invoke the power of his soul stone 3 times per day as a swift action, enabling him to grow in size as if using enlarge person (even if he is not a humanoid).
What is the duration of the Enlargment? Character Level, Caster Level, or Class Level?
from the spell-like abilities in the magic section of the core rule book:
"If a character class grants a spell-like ability that is not based on an actual spell, the ability’s effective spell level is equal to the highest-level class spell the character can cast, and is cast at the class level the ability is gained."
the part about it not based on actual spell is more to do with how to count the spell level. but the caster level should be he same even in sla taht are like actual spells.