Magical Leech

These look like normal leeches but for faint purple sparks that sometimes crackle from their bloated bodies. They are mute and make no attempt to communicate.

Magical leeches feed without contact, drawing magic from anyone within 1 yard, so victims seldom feel anything. With any leech that close, a caster must pass an Intelligence or Wisdom check, as appropriate, or the spell fizzles. Each round there is a 10% chance plus 1% per nearby leech that a memorized spell is drained, highest level first and random among equals, unnoticed until the caster tries to use it.

They also feed on magic items, though they prefer energy from minds: each round brings a chance of 5%, plus 1% for each leech, of destroying a random power, function or plus of an item.

When touched, a leech discharges stored energy as a shock dealing 1-2 points plus 1 per spell, ability or other essence eaten in the past 8 hours.

They live in swamps or tall wet grass and never leave on their own; a site holds 5-30, and anyone passing through picks up 1d6.

Gorged, a leech drops off the moment its host enters a wetland where it can spawn, and the stolen magic lets it birth 1-6 young in 3d4 days.