Merform (3.5e Spell)

''You push your legs together and they melt into a single fin, covering itself in glittering scales. Now that you are half-fish you can swim in the depths with ease.''

You transform into a mer-creature version of yourself. You gain the aquatic subtype for the duration, and are able to breathe in both air and water. You gain a swim speed equal to your land speed, you can take 10 on swim checks even if rushed or threatened, and gain a +8 bonus on Swim checks. You are unaffected by water pressure, and gain blindsense out to 60 feet, but only underwater. Any melee or ranged weapons you wield are unaffected by the water as if you were under freedom of movement (normally, slashing, bludgeoning, and ranged attacks are hampered by water).

Because your legs have become fins, your movement on land is hampered, reduced to 5 feet.