Prerequisite: Pact of the Chain feature
When you cast Find Familiar, you infuse the summoned familiar with a measure of your eldritch power, granting the creature the following benefits:
• The familiar gains either a flying speed or a     swimming speed (your choice) of 40 feet.
• As a bonus action, you can command the     familiar to take the Attack action.
• The familiar's weapon attacks are considered     magical for the purpose of overcoming     immunity and resistance to nonmagical     attacks.
• If the familiar forces a creature to make a     saving throw, it uses your spell save DC.
• When the familiar takes damage, you can use     your reaction to grant it resistance against that     damage.
Prerequisite: Eldritch Blast cantrip
Once on each of your turns when you hit a creature with your Eldritch Blast, you can move that creature in a straight line 10 feet closer to yourself.
Prerequisite: 5th level
You can breathe underwater, and you gain a swimming speed equal to your walking speed.
You can also cast Water Breathing without expending a spell slot. You regain the ability to do so when you finish a long rest.
Prerequisite: 7th level
As an action, you gain the ability to see through solid objects to a range of 30 feet. Within that range, you have darkvision if you don't already have it. This special sight lasts for 1 minute or until your concentration ends (as if you were concentrating on a spell). During that time, you perceive objects as ghostly, transparent images.
Once you use this invocation, you can't use it again until you finish a short or long rest.