the item appears as a golden orb that radiates magical energy through cut out  lines that circle it. as an action, you can throw it to any place within a range of 60 feet. upon impact, it creates a great flash of wild magic energy before dissipating. all creatures in a 20 foot radius of the grenades impact site must make a DC 15 wisdom saving throw. on a failed save they are blinded until the end of its next turn and are affected by the item's wild magic table for 1 minute. on a successful save, a target must roll a d20, on the result of a 1 they are affected by the item's wild magic table until the end of their next turn. when a creature affected by the wild magic effect of the item casts a spell of 1st level or higher, it must roll on the wild magic table. the wild magic effect replaces the effect of the spell. at the end of each turn an affected creature can repeat the saving throw. if it succeeds, this effect ends for that creature.

the item has 5 charges and regains 1d4 - 1 charges daily at dawn (minimum of 1). if you expend the last charge, roll a d20. On a 1, the item disintegrates into nothing and is destroyed.

Wild Magic table

d100

• 01-05: You overload on magical energy but to no avail, you take one level of exhaustion.
• 06-10: Your spell affects a different area or target than intended, determined by the DM.
• 11-15: You cast Cloudkill as a 5th-level spell centered on yourself.
• 16-20: You summon a random creature with a max CR of 3 that is hostile towards all other creatures.
• 21-25: Make a Constitution saving throw or become petrified for 1d4 + 1 rounds or until a Greater Restoration spell is cast on you.
• 26-30: You teleport up to 500 ft in a random direction.
• 31-35: You shrink down by two size categories as if affected by a Reduce effect of Enlarge/Reduce.
• 36-40: You are transported to a random plane of existence for 1d6 rounds and return at the beginning of your turn.
• 41-45: Make a wisdom saving throw or become affected by Short-Term Madness.
• 46-50: You cast Sleep centered on yourself as a 4th-level spell.
• 51-55: You suddenly burst into flames and take 2d8 fire damage each round, you must make a dexterity saving throw at the end of your turn to end the effect.
• 56-60: You cast Polymorph on yourself. If you fail the saving throw, you turn into a sheep for the spell's duration.
• 61-65: You are sent flying up into the air by magical winds before falling back down. make a strength saving throw, on a failed save you take 3d6 Bludgeoning damage or half as much on a successful one.
• 66-70: Make a constitution saving throw or be cursed with lycanthropy for 1d6 x 5 hours. you lose control of your character for the duration and become frightened by party members.
• 71-75: You suddenly feel a slight rumbling that gets louder and louder. a fissure appears with 60 feet of you as if created by the Earthquake spell.
• 76-80: You and Up to three creatures you choose within 60 feet of you take 3d10 lightning damage.
• 81-85: A random creature becomes hostile towards you for 1d4 + 2 rounds and will actively try to harm you, ignoring other creatures.
• 86-90: You cast Conjure Minor Elementals centered on yourself as a 5th-level spell. all summoned creatures are hostile towards all other targets within 60 feet (including you).
• 91-95: You feel a great force within you come out as a massive Burp. make a constitution saving throw or become stunned. each creature within 30 feet of you must make a constitution saving throw. on a failed save they take 3d10 thunder damage, are pushed back five feet, and are knocked prone. on a successful save they take half damage and are not pushed or fall prone.
• 96-00: the table affects you for one minute longer and you gain disadvantage on your next 1d6 checks to end the effect.

Notes: to create the item you must follow the prerequisites for crafting a regular magic item in the DMG or the XGtE. you must also find a place where wild magic is prevalent and atain resources within the area or even craft the item there. find such a zone might require research time and can be considered part of the crafting process.