"Considering your statures, let's start with the upward slash."

Mentor of the Meek

Whenever another creature you control with power 2 or less enters, you may pay {1}. If you do, draw a card.

Foundations Jumpstart

"In these halls there is no pass or fail. Your true test comes with the first full moon."

Foundations

The List

In a twinkling the table was laid. There was hot soup, cold meats, a blackberry tart, new loaves, slabs of butter, and half a ripe cheese: good plain food, as good as the Shire could show.

Tales of Middle-earth Commander

Whenever another creature with power 2 or less enters the battlefield under your control, you may pay {1}. If you do, draw a card.

March of the Machine Commander

If one or more static abilities that apply to a creature entering change its power, those abilities are considered when determining whether Mentor of the Meek's ability triggers. The same is true for replacement effects that apply to it, such as entering with one or more +1/+1 counters or entering as a copy of another creature.

Mentor of the Meek's ability checks the power of the other creature only as it enters. If that creature's power is 2 or less, the ability will trigger. Once the ability triggers, raising that creature's power above 2 won't affect that ability. Similarly, reducing the creature's power to 2 or less after it enters won't cause the ability to trigger.

While resolving the triggered ability of Mentor of the Meek, you can't pay {1} multiple times to draw more than one card.