There are many options, as a function of mechanics and fluff. I will present an option that can mechanically represent what you want but that requires refluffing. A brawler fighter accepts this without fluffing, but has difficulty performing well without significant complexity on the battlefield.
- Must be a Dwarf
- Must be playable from 1 for a campaign
- Must emphasise grapples and doing damage with them
The core theme of this class is unarmed or "obligatory spiky bits" damage. Grapples would be lovely, as well as thematically appropriate actions.
For our at-will grabs, we have 3 possible actions, ignoring fluff:
- Garotte Strangle (Assassin)
- Net Snare (Feat)
- Grappling Strike (Fighter)
For storm of obligatory spiky bits, the spiked gauntlet is +2/1d6 (uuugh) with off-hand and unarmed group. The wrist razor is... spiky and keeps your hand free, but is +3/1d4. On the other hand it's a light blade and keeps your hands slot free.
There are too many light-blade options to list.
This character keeps feeling like a striker to me, albeit one that's tough and has a lot of single-target lockdown to me.
Mechanically speaking, I see this character swarming onto someone and then popping off their head.
I also see them moving into someone's space and holding on.
In a sense a druid grabber could be highly effective in this circumstance. While it would need significant refluffing, the druid (besides the monk) is most comfortable with "natural attacks." At the same time, there are a significant number of brawler fighter feats that are a "sine qua non" of a grabber.
A druid's ruthless killer + grasping claws can immobilize targets as well as doing very credible damage to them. In terms of simulating a grab that actually works, there is nothing more effective. Obviously the beast form stuff would have to be refluffed, or you could go with "silverback gorilla" or equivalent. The primal guardian works exceptionally well with a dwarf, and the coiled serpent PP fits your mechanics well (obviously requiring refluffing to fit your desired visual).
With claw gloves and the right combat advantage feats, you can be a very very credible striker as a druid. With primal guardian, hide armor, and your high con, you'll have an acceptable defense, and your immobilization provides highly acceptable lockdown. Grab the guardian theme for a bit of defender sprinkled in, and make sure to articulate your fluff well. There is nothing preventing you from spending the majority of your time in "beast form" and thereby choosing powers that synergize well.
There's generally a power every level that fits into your concept, so having something fun and interesting to do is not out of the question, and the "vicious advantage" feat grants CA against immobilized enemies, allowing you to grant yourself CA (and thereby bonus damage with your claw gloves.)