Here's a closer look at the Tails Floater Keychain.
This soft foam type of key chain is coated with a soft rubbery plastic so you can squeeze it. More importantly, anything attached to it will float if dropped in water. This is part of a set, seen earlier on Keychains 1.
It's a nice bright yellow cut square-ish shape with happy arms-crossed Tails in a ring with lightening-bolt shapes next to him, above the "Segasonic" banner. This keychain is uncommon.